Init

2026-01-10 22:07:59 -05:00 · 2023-12-26 10:45:31 -08:00
2980 changed files with 83827 additions and 137146 deletions
--- a/.bazelrc
+++ b/.bazelrc
@@ -6,12 +6,6 @@ import %workspace%/build/bazelrc/debug.bazelrc
 import %workspace%/build/bazelrc/hermetic-cc.bazelrc
 import %workspace%/build/bazelrc/performance.bazelrc

-# hermetic_cc_toolchain v3.0.1 required changes.
-common --enable_platform_specific_config
-build:linux --sandbox_add_mount_pair=/tmp
-build:macos --sandbox_add_mount_pair=/var/tmp
-build:windows --sandbox_add_mount_pair=C:\Temp
-
 # E2E run with debug gotag
 test:e2e --define gotags=debug

@@ -22,7 +16,6 @@ coverage --define=coverage_enabled=1
 build --workspace_status_command=./hack/workspace_status.sh

 build --define blst_disabled=false
-build --compilation_mode=opt
 run --define blst_disabled=false

 build:blst_disabled --define blst_disabled=true
--- a/.bazelversion
+++ b/.bazelversion
@@ -1 +1 @@
-7.1.0
+6.4.0
--- a/.buildkite-bazelrc
+++ b/.buildkite-bazelrc
@@ -10,9 +10,10 @@

 # Prysm specific remote-cache properties.
 build:remote-cache --remote_download_minimal
-build:remote-cache --remote_build_event_upload=minimal
+build:remote-cache --experimental_remote_build_event_upload=minimal
 build:remote-cache --remote_cache=grpc://bazel-remote-cache:9092
-build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
+# Does not work with rules_oci. See https://github.com/bazel-contrib/rules_oci/issues/292
+#build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
 build:remote-cache --remote_local_fallback
 build:remote-cache --experimental_remote_cache_async
 build:remote-cache --experimental_remote_merkle_tree_cache
--- a/.deepsource.toml
+++ b/.deepsource.toml
@@ -11,7 +11,7 @@ name = "go"
 enabled = true

 [analyzers.meta]
-import_paths = ["github.com/prysmaticlabs/prysm/v5"]
+import_paths = ["github.com/prysmaticlabs/prysm/v4"]

 [[analyzers]]
 name = "test-coverage"
--- a/.github/actions/gomodtidy/Dockerfile
+++ b/.github/actions/gomodtidy/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.22-alpine
+FROM golang:1.21-alpine

 COPY entrypoint.sh /entrypoint.sh

--- a/.github/workflows/fuzz.yml
+++ b/.github/workflows/fuzz.yml
@@ -16,7 +16,7 @@ jobs:
      - uses: actions/checkout@v3
      - uses: actions/setup-go@v4
        with:
-          go-version: '1.22.3'
+          go-version: '1.21.5'
      - id: list
        uses: shogo82148/actions-go-fuzz/list@v0
        with:
@@ -36,7 +36,7 @@ jobs:
      - uses: actions/checkout@v3
      - uses: actions/setup-go@v4
        with:
-          go-version: '1.22.3'
+          go-version: '1.21.5'
      - uses: shogo82148/actions-go-fuzz/run@v0
        with:
          packages: ${{ matrix.package }}
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -28,14 +28,14 @@ jobs:
    steps:
      - name: Checkout
        uses: actions/checkout@v2
-      - name: Set up Go 1.22
+      - name: Set up Go 1.21
        uses: actions/setup-go@v3
        with:
-          go-version: '1.22.3'
+          go-version: '1.21.5'
      - name: Run Gosec Security Scanner
        run: | # https://github.com/securego/gosec/issues/469
          export PATH=$PATH:$(go env GOPATH)/bin
-          go install github.com/securego/gosec/v2/cmd/gosec@v2.19.0
+          go install github.com/securego/gosec/v2/cmd/gosec@v2.15.0
          gosec -exclude-generated -exclude=G307 -exclude-dir=crypto/bls/herumi ./...

  lint:
@@ -45,16 +45,16 @@ jobs:
      - name: Checkout
        uses: actions/checkout@v2

-      - name: Set up Go 1.22
+      - name: Set up Go 1.21
        uses: actions/setup-go@v3
        with:
-          go-version: '1.22.6'
+          go-version: '1.21.5'
          id: go

      - name: Golangci-lint
        uses: golangci/golangci-lint-action@v3
        with:
-          version: v1.60.2
+          version: v1.55.2
          args: --config=.golangci.yml --out-${NO_FUTURE}format colored-line-number

  build:
@@ -64,7 +64,7 @@ jobs:
      - name: Set up Go 1.x
        uses: actions/setup-go@v2
        with:
-          go-version: '1.22.6'
+          go-version: '1.21.5'
        id: go

      - name: Check out code into the Go module directory
--- a/.gitignore
+++ b/.gitignore
@@ -41,6 +41,3 @@ jwt.hex

 # manual testing
 tmp
-
-# spectest coverage reports
-report.txt
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -6,7 +6,7 @@ run:
    - proto
    - tools/analyzers
  timeout: 10m
-  go: '1.22.6'
+  go: '1.21.5'

 linters:
  enable-all: true
@@ -34,6 +34,7 @@ linters:
    - dogsled
    - dupl
    - durationcheck
+    - errorlint
    - exhaustive
    - exhaustruct
    - forbidigo
@@ -51,7 +52,6 @@ linters:
    - gofumpt
    - gomnd
    - gomoddirectives
-    - gosec
    - inamedparam
    - interfacebloat
    - ireturn
@@ -80,6 +80,7 @@ linters:
    - thelper
    - unparam
    - varnamelen
+    - wastedassign
    - wrapcheck
    - wsl

--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -12,7 +12,7 @@ exports_files([
    "LICENSE.md",
 ])

-# gazelle:prefix github.com/prysmaticlabs/prysm/v5
+# gazelle:prefix github.com/prysmaticlabs/prysm/v4
 # gazelle:map_kind go_library go_library @prysm//tools/go:def.bzl
 # gazelle:map_kind go_test go_test @prysm//tools/go:def.bzl
 # gazelle:map_kind go_repository go_repository @prysm//tools/go:def.bzl
@@ -194,6 +194,33 @@ nogo(
    config = ":nogo_config_with_excludes",
    visibility = ["//visibility:public"],
    deps = [
+        "@org_golang_x_tools//go/analysis/passes/unsafeptr:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/unreachable:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/unmarshal:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/tests:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/structtag:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/stdmethods:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/shift:go_default_library",
+        # "@org_golang_x_tools//go/analysis/passes/shadow:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/printf:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/pkgfact:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/nilness:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/nilfunc:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/loopclosure:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/httpresponse:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/findcall:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/deepequalerrors:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/ctrlflow:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/copylock:go_default_library",
+        #  "@org_golang_x_tools//go/analysis/passes/cgocall:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/buildtag:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/buildssa:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/bools:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/atomicalign:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/atomic:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/assign:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/inspect:go_default_library",
+        "@org_golang_x_tools//go/analysis/passes/asmdecl:go_default_library",
        "//tools/analyzers/comparesame:go_default_library",
        "//tools/analyzers/cryptorand:go_default_library",
        "//tools/analyzers/errcheck:go_default_library",
@@ -209,54 +236,6 @@ nogo(
        "//tools/analyzers/shadowpredecl:go_default_library",
        "//tools/analyzers/slicedirect:go_default_library",
        "//tools/analyzers/uintcast:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/appends:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/asmdecl:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/assign:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/atomic:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/atomicalign:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/bools:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/buildssa:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/buildtag:go_default_library",
-        # cgocall disabled
-        #"@org_golang_x_tools//go/analysis/passes/cgocall:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/copylock:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/ctrlflow:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/deepequalerrors:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/defers:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/directive:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/errorsas:go_default_library",
-        # fieldalignment disabled
-        #"@org_golang_x_tools//go/analysis/passes/fieldalignment:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/findcall:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/framepointer:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/httpmux:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/httpresponse:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/ifaceassert:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/inspect:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/loopclosure:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/nilfunc:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/nilness:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/pkgfact:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/printf:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/reflectvaluecompare:go_default_library",
-        # shadow disabled
-        #"@org_golang_x_tools//go/analysis/passes/shadow:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/shift:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/sigchanyzer:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/slog:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/sortslice:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/stdmethods:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/stringintconv:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/structtag:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/testinggoroutine:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/tests:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/timeformat:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unmarshal:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unreachable:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unsafeptr:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unusedresult:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/unusedwrite:go_default_library",
-        "@org_golang_x_tools//go/analysis/passes/usesgenerics:go_default_library",
    ] + select({
        # nogo checks that fail with coverage enabled.
        ":coverage_enabled": [],
--- a/DEPENDENCIES.md
+++ b/DEPENDENCIES.md
@@ -55,7 +55,7 @@ bazel build //beacon-chain --config=release
 ## Adding / updating dependencies

 1. Add your dependency as you would with go modules. I.e. `go get ...`
-1. Run `bazel run //:gazelle -- update-repos -from_file=go.mod` to update the bazel managed dependencies.
+1. Run `gazelle update-repos -from_file=go.mod` to update the bazel managed dependencies.

 Example:

--- a/INTEROP.md
+++ b/INTEROP.md
@@ -30,6 +30,9 @@ You can use `bazel run //tools/genesis-state-gen` to create a deterministic gene
 - **--output-ssz** string: Output filename of the SSZ marshaling of the generated genesis state
 - **--config-name=interop** string: name of the beacon chain config to use when generating the state. ex mainnet|minimal|interop

+**deprecated flag: use --config-name instead**
+- **--mainnet-config** bool: Select whether genesis state should be generated with mainnet or minimal (default) params
+
 The example below creates 64 validator keys, instantiates a genesis state with those 64 validators and with genesis unix timestamp 1567542540,
 and finally writes a ssz encoded output to ~/Desktop/genesis.ssz. This file can be used to kickstart the beacon chain in the next section. When using the `--interop-*` flags, the beacon node will assume the `interop` config should be used, unless a different config is specified on the command line.

--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -1,6 +0,0 @@
-###############################################################################
-# Bazel now uses Bzlmod by default to manage external dependencies.
-# Please consider migrating your external dependencies from WORKSPACE to MODULE.bazel.
-#
-# For more details, please check https://github.com/bazelbuild/bazel/issues/18958
-###############################################################################
--- a/MODULE.bazel.lock
+++ b/MODULE.bazel.lock
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@

 [![Build status](https://badge.buildkite.com/b555891daf3614bae4284dcf365b2340cefc0089839526f096.svg?branch=master)](https://buildkite.com/prysmatic-labs/prysm)
 [![Go Report Card](https://goreportcard.com/badge/github.com/prysmaticlabs/prysm)](https://goreportcard.com/report/github.com/prysmaticlabs/prysm)
-[![Consensus_Spec_Version 1.4.0](https://img.shields.io/badge/Consensus%20Spec%20Version-v1.4.0-blue.svg)](https://github.com/ethereum/consensus-specs/tree/v1.4.0)
+[![Consensus_Spec_Version 1.3.0](https://img.shields.io/badge/Consensus%20Spec%20Version-v1.3.0-blue.svg)](https://github.com/ethereum/consensus-specs/tree/v1.3.0)
 [![Execution_API_Version 1.0.0-beta.2](https://img.shields.io/badge/Execution%20API%20Version-v1.0.0.beta.2-blue.svg)](https://github.com/ethereum/execution-apis/tree/v1.0.0-beta.2/src/engine)
 [![Discord](https://user-images.githubusercontent.com/7288322/34471967-1df7808a-efbb-11e7-9088-ed0b04151291.png)](https://discord.gg/prysmaticlabs)
 [![GitPOAP Badge](https://public-api.gitpoap.io/v1/repo/prysmaticlabs/prysm/badge)](https://www.gitpoap.io/gh/prysmaticlabs/prysm)
--- a/94
+++ b/94
@@ -16,20 +16,34 @@ load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")

 rules_pkg_dependencies()

-HERMETIC_CC_TOOLCHAIN_VERSION = "v3.0.1"
-
 http_archive(
    name = "hermetic_cc_toolchain",
-    sha256 = "3bc6ec127622fdceb4129cb06b6f7ab098c4d539124dde96a6318e7c32a53f7a",
+    sha256 = "973ab22945b921ef45b8e1d6ce01ca7ce1b8a462167449a36e297438c4ec2755",
+    strip_prefix = "hermetic_cc_toolchain-5098046bccc15d2962f3cc8e7e53d6a2a26072dc",
    urls = [
-        "https://mirror.bazel.build/github.com/uber/hermetic_cc_toolchain/releases/download/{0}/hermetic_cc_toolchain-{0}.tar.gz".format(HERMETIC_CC_TOOLCHAIN_VERSION),
-        "https://github.com/uber/hermetic_cc_toolchain/releases/download/{0}/hermetic_cc_toolchain-{0}.tar.gz".format(HERMETIC_CC_TOOLCHAIN_VERSION),
+        "https://github.com/uber/hermetic_cc_toolchain/archive/5098046bccc15d2962f3cc8e7e53d6a2a26072dc.tar.gz",  # 2023-06-28
    ],
 )

 load("@hermetic_cc_toolchain//toolchain:defs.bzl", zig_toolchains = "toolchains")

-zig_toolchains()
+# Temporarily use a nightly build until 0.12.0 is released.
+# See: https://github.com/prysmaticlabs/prysm/issues/13130
+zig_toolchains(
+    host_platform_sha256 = {
+        "linux-aarch64": "45afb8e32adde825165f4f293fcea9ecea503f7f9ec0e9bf4435afe70e67fb70",
+        "linux-x86_64": "f136c6a8a0f6adcb057d73615fbcd6f88281b3593f7008d5f7ed514ff925c02e",
+        "macos-aarch64": "05d995853c05243151deff47b60bdc2674f1e794a939eaeca0f42312da031cee",
+        "macos-x86_64": "721754ba5a50f31e8a1f0e1a74cace26f8246576878ac4a8591b0ee7b6db1fc1",
+        "windows-x86_64": "93f5248b2ea8c5ee8175e15b1384e133edc1cd49870b3ea259062a2e04164343",
+    },
+    url_formats = [
+        "https://ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
+        "https://mirror.bazel.build/ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
+        "https://prysmaticlabs.com/mirror/ziglang.org/builds/zig-{host_platform}-{version}.{_ext}",
+    ],
+    version = "0.12.0-dev.1349+fa022d1ec",
+)

 # Register zig sdk toolchains with support for Ubuntu 20.04 (Focal Fossa) which has an EOL date of April, 2025.
 # For ubuntu glibc support, see https://launchpad.net/ubuntu/+source/glibc
@@ -67,10 +81,10 @@ bazel_skylib_workspace()

 http_archive(
    name = "bazel_gazelle",
-    integrity = "sha256-MpOL2hbmcABjA1R5Bj2dJMYO2o15/Uc5Vj9Q0zHLMgk=",
+    sha256 = "d3fa66a39028e97d76f9e2db8f1b0c11c099e8e01bf363a923074784e451f809",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.35.0/bazel-gazelle-v0.35.0.tar.gz",
-        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.35.0/bazel-gazelle-v0.35.0.tar.gz",
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-gazelle/releases/download/v0.33.0/bazel-gazelle-v0.33.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-gazelle/releases/download/v0.33.0/bazel-gazelle-v0.33.0.tar.gz",
    ],
 )

@@ -92,20 +106,6 @@ load("@rules_distroless//distroless:dependencies.bzl", "rules_distroless_depende

 rules_distroless_dependencies()

-http_archive(
-    name = "distroless",
-    integrity = "sha256-Cf00kUp1NyXA3LzbdyYy4Kda27wbkB8+A9MliTxq4jE=",
-    strip_prefix = "distroless-9dc924b9fe812eec2fa0061824dcad39eb09d0d6",
-    url = "https://github.com/GoogleContainerTools/distroless/archive/9dc924b9fe812eec2fa0061824dcad39eb09d0d6.tar.gz",  # 2024-01-24
-)
-
-http_archive(
-    name = "aspect_bazel_lib",
-    sha256 = "f5ea76682b209cc0bd90d0f5a3b26d2f7a6a2885f0c5f615e72913f4805dbb0d",
-    strip_prefix = "bazel-lib-2.5.0",
-    url = "https://github.com/aspect-build/bazel-lib/releases/download/v2.5.0/bazel-lib-v2.5.0.tar.gz",
-)
-
 load("@aspect_bazel_lib//lib:repositories.bzl", "aspect_bazel_lib_dependencies", "aspect_bazel_lib_register_toolchains")

 aspect_bazel_lib_dependencies()
@@ -114,9 +114,9 @@ aspect_bazel_lib_register_toolchains()

 http_archive(
    name = "rules_oci",
-    sha256 = "4a276e9566c03491649eef63f27c2816cc222f41ccdebd97d2c5159e84917c3b",
-    strip_prefix = "rules_oci-1.7.4",
-    url = "https://github.com/bazel-contrib/rules_oci/releases/download/v1.7.4/rules_oci-v1.7.4.tar.gz",
+    sha256 = "c71c25ed333a4909d2dd77e0b16c39e9912525a98c7fa85144282be8d04ef54c",
+    strip_prefix = "rules_oci-1.3.4",
+    url = "https://github.com/bazel-contrib/rules_oci/releases/download/v1.3.4/rules_oci-v1.3.4.tar.gz",
 )

 load("@rules_oci//oci:dependencies.bzl", "rules_oci_dependencies")
@@ -137,10 +137,10 @@ http_archive(
        # Expose internals of go_test for custom build transitions.
        "//third_party:io_bazel_rules_go_test.patch",
    ],
-    sha256 = "80a98277ad1311dacd837f9b16db62887702e9f1d1c4c9f796d0121a46c8e184",
+    sha256 = "d6ab6b57e48c09523e93050f13698f708428cfd5e619252e369d377af6597707",
    urls = [
-        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.46.0/rules_go-v0.46.0.zip",
-        "https://github.com/bazelbuild/rules_go/releases/download/v0.46.0/rules_go-v0.46.0.zip",
+        "https://mirror.bazel.build/github.com/bazelbuild/rules_go/releases/download/v0.43.0/rules_go-v0.43.0.zip",
+        "https://github.com/bazelbuild/rules_go/releases/download/v0.43.0/rules_go-v0.43.0.zip",
    ],
 )

@@ -182,14 +182,10 @@ load("@io_bazel_rules_go//go:deps.bzl", "go_register_toolchains", "go_rules_depe
 go_rules_dependencies()

 go_register_toolchains(
-    go_version = "1.22.4",
+    go_version = "1.21.5",
    nogo = "@//:nogo",
 )

-load("//:distroless_deps.bzl", "distroless_deps")
-
-distroless_deps()
-
 http_archive(
    name = "io_kubernetes_build",
    sha256 = "b84fbd1173acee9d02a7d3698ad269fdf4f7aa081e9cecd40e012ad0ad8cfa2a",
@@ -227,7 +223,7 @@ filegroup(
    url = "https://github.com/ethereum/EIPs/archive/5480440fe51742ed23342b68cf106cefd427e39d.tar.gz",
 )

-consensus_spec_version = "v1.5.0-alpha.3"
+consensus_spec_version = "v1.4.0-beta.5"

 bls_test_version = "v0.1.1"

@@ -243,7 +239,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-+byv+GUOQytex5GgtjBGVoNDseJZbiBdAjEtlgCbjEo=",
+    sha256 = "9017ffff84d64a7c4c9e6ff9f421f9479f71d3b463b738f54e02158dbb4f50f0",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )

@@ -259,7 +255,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-JJUy/jT1h3kGQkinTuzL7gMOA1+qgmPgJXVrYuH63Cg=",
+    sha256 = "f08711682553fe7c9362f1400ed8c56b2fa9576df08581fcad4c508ba8ad4788",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )

@@ -275,7 +271,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-T2VM4Qd0SwgGnTjWxjOX297DqEsovO9Ueij1UEJy48Y=",
+    sha256 = "7ea3189e3879f2ac62467cbf2945c00b6c94d30cdefb2d645c630b1018c50e10",
    url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )

@@ -290,7 +286,7 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    integrity = "sha256-OP9BCBcQ7i+93bwj7ktY8pZ5uWsGjgTe4XTp7BDhX+I=",
+    sha256 = "4119992a2efc79e5cb2bdc07ed08c0b1fa32332cbd0d88e6467f34938df97026",
    strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
    url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )
@@ -321,9 +317,9 @@ filegroup(
    visibility = ["//visibility:public"],
 )
    """,
-    sha256 = "77e7e3ed65e33b7bb19d30131f4c2bb39e4dfeb188ab9ae84651c3cc7600131d",
-    strip_prefix = "eth2-networks-934c948e69205dcf2deb87e4ae6cc140c335f94d",
-    url = "https://github.com/eth-clients/eth2-networks/archive/934c948e69205dcf2deb87e4ae6cc140c335f94d.tar.gz",
+    sha256 = "2701e1e1a3ec10c673fe7dbdbbe6f02c8ae8c922aebbf6e720d8c72d5458aafe",
+    strip_prefix = "eth2-networks-7b4897888cebef23801540236f73123e21774954",
+    url = "https://github.com/eth-clients/eth2-networks/archive/7b4897888cebef23801540236f73123e21774954.tar.gz",
 )

 http_archive(
@@ -332,22 +328,22 @@ http_archive(
 filegroup(
    name = "configs",
    srcs = [
-        "metadata/config.yaml",
+        "custom_config_data/config.yaml",
    ],
    visibility = ["//visibility:public"],
 )
 """,
-    integrity = "sha256-b7ZTT+olF+VXEJYNTV5jggNtCkt9dOejm1i2VE+zy+0=",
-    strip_prefix = "holesky-874c199423ccd180607320c38cbaca05d9a1573a",
-    url = "https://github.com/eth-clients/holesky/archive/874c199423ccd180607320c38cbaca05d9a1573a.tar.gz",  # 2024-06-18
+    sha256 = "9f66d8d5644982d3d0d2e3d2b9ebe77a5f96638a5d7fcd715599c32818195cb3",
+    strip_prefix = "holesky-ea39b9006210848e13f28d92e12a30548cecd41d",
+    url = "https://github.com/eth-clients/holesky/archive/ea39b9006210848e13f28d92e12a30548cecd41d.tar.gz",  # 2023-09-21
 )

 http_archive(
    name = "com_google_protobuf",
-    sha256 = "9bd87b8280ef720d3240514f884e56a712f2218f0d693b48050c836028940a42",
-    strip_prefix = "protobuf-25.1",
+    sha256 = "4e176116949be52b0408dfd24f8925d1eb674a781ae242a75296b17a1c721395",
+    strip_prefix = "protobuf-23.3",
    urls = [
-        "https://github.com/protocolbuffers/protobuf/archive/v25.1.tar.gz",
+        "https://github.com/protocolbuffers/protobuf/archive/v23.3.tar.gz",
    ],
 )

--- a/api/BUILD.bazel
+++ b/api/BUILD.bazel
@@ -1,24 +1,11 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+load("@prysm//tools/go:def.bzl", "go_library")

 go_library(
    name = "go_default_library",
    srcs = [
        "constants.go",
        "headers.go",
-        "jwt.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api",
    visibility = ["//visibility:public"],
-    deps = [
-        "//crypto/rand:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["jwt_test.go"],
-    embed = [":go_default_library"],
-    deps = ["//testing/require:go_default_library"],
 )
--- a/api/client/BUILD.bazel
+++ b/api/client/BUILD.bazel
@@ -7,7 +7,7 @@ go_library(
        "errors.go",
        "options.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client",
    visibility = ["//visibility:public"],
    deps = ["@com_github_pkg_errors//:go_default_library"],
 )
--- a/api/client/beacon/BUILD.bazel
+++ b/api/client/beacon/BUILD.bazel
@@ -6,17 +6,17 @@ go_library(
        "checkpoint.go",
        "client.go",
        "doc.go",
-        "health.go",
-        "log.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/beacon",
    visibility = ["//visibility:public"],
    deps = [
        "//api/client:go_default_library",
-        "//api/client/beacon/iface:go_default_library",
        "//api/server:go_default_library",
-        "//api/server/structs:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
+        "//beacon-chain/rpc/eth/beacon:go_default_library",
+        "//beacon-chain/rpc/eth/config:go_default_library",
+        "//beacon-chain/rpc/eth/shared:go_default_library",
+        "//beacon-chain/rpc/prysm/beacon:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//consensus-types/interfaces:go_default_library",
        "//consensus-types/primitives:go_default_library",
@@ -39,12 +39,10 @@ go_test(
    srcs = [
        "checkpoint_test.go",
        "client_test.go",
-        "health_test.go",
    ],
    embed = [":go_default_library"],
    deps = [
        "//api/client:go_default_library",
-        "//api/client/beacon/testing:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/blocks:go_default_library",
@@ -58,6 +56,5 @@ go_test(
        "//testing/util:go_default_library",
        "//time/slots:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
-        "@org_uber_go_mock//gomock:go_default_library",
    ],
 )
--- a/api/client/beacon/checkpoint.go
+++ b/api/client/beacon/checkpoint.go
@@ -7,17 +7,17 @@ import (

 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	base "github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/encoding/ssz/detect"
-	"github.com/prysmaticlabs/prysm/v5/io/file"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
-	"github.com/sirupsen/logrus"
+	base "github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/encoding/ssz/detect"
+	"github.com/prysmaticlabs/prysm/v4/io/file"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
+	"github.com/prysmaticlabs/prysm/v4/time/slots"
+	log "github.com/sirupsen/logrus"
 	"golang.org/x/mod/semver"
 )

@@ -74,12 +74,7 @@ func DownloadFinalizedData(ctx context.Context, client *Client) (*OriginData, er
 	if err != nil {
 		return nil, errors.Wrap(err, "error detecting chain config for finalized state")
 	}
-
-	log.WithFields(logrus.Fields{
-		"name": vu.Config.ConfigName,
-		"fork": version.String(vu.Fork),
-	}).Info("Detected supported config in remote finalized state")
-
+	log.Printf("detected supported config in remote finalized state, name=%s, fork=%s", vu.Config.ConfigName, version.String(vu.Fork))
 	s, err := vu.UnmarshalBeaconState(sb)
 	if err != nil {
 		return nil, errors.Wrap(err, "error unmarshaling finalized state to correct version")
@@ -113,10 +108,10 @@ func DownloadFinalizedData(ctx context.Context, client *Client) (*OriginData, er
 	}

 	log.
-		WithField("blockSlot", b.Block().Slot()).
-		WithField("stateSlot", s.Slot()).
-		WithField("stateRoot", hexutil.Encode(sr[:])).
-		WithField("blockRoot", hexutil.Encode(br[:])).
+		WithField("block_slot", b.Block().Slot()).
+		WithField("state_slot", s.Slot()).
+		WithField("state_root", hexutil.Encode(sr[:])).
+		WithField("block_root", hexutil.Encode(br[:])).
 		Info("Downloaded checkpoint sync state and block.")
 	return &OriginData{
 		st: s,
--- a/api/client/beacon/checkpoint_test.go
+++ b/api/client/beacon/checkpoint_test.go
@@ -9,20 +9,22 @@ import (
 	"net/http"
 	"testing"

+	"github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	blocktest "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks/testing"
+	"github.com/prysmaticlabs/prysm/v4/network/forks"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/util"
+	"github.com/prysmaticlabs/prysm/v4/time/slots"
+
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/ssz/detect"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
+
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	blocktest "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks/testing"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/ssz/detect"
-	"github.com/prysmaticlabs/prysm/v5/network/forks"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/testing/util"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 type testRT struct {
--- a/api/client/beacon/client.go
+++ b/api/client/beacon/client.go
@@ -15,14 +15,17 @@ import (

 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/api/server"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/network/forks"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/sirupsen/logrus"
+	"github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/api/server"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/beacon"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/config"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/shared"
+	apibeacon "github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/prysm/beacon"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/network/forks"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	log "github.com/sirupsen/logrus"
 )

 const (
@@ -147,8 +150,8 @@ func (c *Client) GetFork(ctx context.Context, stateId StateOrBlockId) (*ethpb.Fo
 	if err != nil {
 		return nil, errors.Wrapf(err, "error requesting fork by state id = %s", stateId)
 	}
-	fr := &structs.Fork{}
-	dataWrapper := &struct{ Data *structs.Fork }{Data: fr}
+	fr := &shared.Fork{}
+	dataWrapper := &struct{ Data *shared.Fork }{Data: fr}
 	err = json.Unmarshal(body, dataWrapper)
 	if err != nil {
 		return nil, errors.Wrap(err, "error decoding json response in GetFork")
@@ -176,12 +179,12 @@ func (c *Client) GetForkSchedule(ctx context.Context) (forks.OrderedSchedule, er
 }

 // GetConfigSpec retrieve the current configs of the network used by the beacon node.
-func (c *Client) GetConfigSpec(ctx context.Context) (*structs.GetSpecResponse, error) {
+func (c *Client) GetConfigSpec(ctx context.Context) (*config.GetSpecResponse, error) {
 	body, err := c.Get(ctx, getConfigSpecPath)
 	if err != nil {
 		return nil, errors.Wrap(err, "error requesting configSpecPath")
 	}
-	fsr := &structs.GetSpecResponse{}
+	fsr := &config.GetSpecResponse{}
 	err = json.Unmarshal(body, fsr)
 	if err != nil {
 		return nil, err
@@ -256,7 +259,7 @@ func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData
 	if err != nil {
 		return nil, err
 	}
-	v := &structs.GetWeakSubjectivityResponse{}
+	v := &apibeacon.GetWeakSubjectivityResponse{}
 	err = json.Unmarshal(body, v)
 	if err != nil {
 		return nil, err
@@ -282,7 +285,7 @@ func (c *Client) GetWeakSubjectivity(ctx context.Context) (*WeakSubjectivityData

 // SubmitChangeBLStoExecution calls a beacon API endpoint to set the withdrawal addresses based on the given signed messages.
 // If the API responds with something other than OK there will be failure messages associated to the corresponding request message.
-func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*structs.SignedBLSToExecutionChange) error {
+func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*shared.SignedBLSToExecutionChange) error {
 	u := c.BaseURL().ResolveReference(&url.URL{Path: changeBLStoExecutionPath})
 	body, err := json.Marshal(request)
 	if err != nil {
@@ -309,9 +312,9 @@ func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*stru
 		}
 		for _, failure := range errorJson.Failures {
 			w := request[failure.Index].Message
-			log.WithFields(logrus.Fields{
-				"validatorIndex":    w.ValidatorIndex,
-				"withdrawalAddress": w.ToExecutionAddress,
+			log.WithFields(log.Fields{
+				"validator_index":    w.ValidatorIndex,
+				"withdrawal_address": w.ToExecutionAddress,
 			}).Error(failure.Message)
 		}
 		return errors.Errorf("POST error %d: %s", errorJson.Code, errorJson.Message)
@@ -321,12 +324,12 @@ func (c *Client) SubmitChangeBLStoExecution(ctx context.Context, request []*stru

 // GetBLStoExecutionChanges gets all the set withdrawal messages in the node's operation pool.
 // Returns a struct representation of json response.
-func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*structs.BLSToExecutionChangesPoolResponse, error) {
+func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*beacon.BLSToExecutionChangesPoolResponse, error) {
 	body, err := c.Get(ctx, changeBLStoExecutionPath)
 	if err != nil {
 		return nil, err
 	}
-	poolResponse := &structs.BLSToExecutionChangesPoolResponse{}
+	poolResponse := &beacon.BLSToExecutionChangesPoolResponse{}
 	err = json.Unmarshal(body, poolResponse)
 	if err != nil {
 		return nil, err
@@ -335,15 +338,15 @@ func (c *Client) GetBLStoExecutionChanges(ctx context.Context) (*structs.BLSToEx
 }

 type forkScheduleResponse struct {
-	Data []structs.Fork
+	Data []shared.Fork
 }

 func (fsr *forkScheduleResponse) OrderedForkSchedule() (forks.OrderedSchedule, error) {
 	ofs := make(forks.OrderedSchedule, 0)
 	for _, d := range fsr.Data {
-		epoch, err := strconv.ParseUint(d.Epoch, 10, 64)
+		epoch, err := strconv.Atoi(d.Epoch)
 		if err != nil {
-			return nil, errors.Wrapf(err, "error parsing epoch %s", d.Epoch)
+			return nil, err
 		}
 		vSlice, err := hexutil.Decode(d.CurrentVersion)
 		if err != nil {
@@ -355,7 +358,7 @@ func (fsr *forkScheduleResponse) OrderedForkSchedule() (forks.OrderedSchedule, e
 		version := bytesutil.ToBytes4(vSlice)
 		ofs = append(ofs, forks.ForkScheduleEntry{
 			Version: version,
-			Epoch:   primitives.Epoch(epoch),
+			Epoch:   primitives.Epoch(uint64(epoch)),
 		})
 	}
 	sort.Sort(ofs)
--- a/api/client/beacon/client_test.go
+++ b/api/client/beacon/client_test.go
@@ -4,8 +4,8 @@ import (
 	"net/url"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestParseNodeVersion(t *testing.T) {
--- a/api/client/beacon/health.go
+++ b/api/client/beacon/health.go
@@ -1,60 +0,0 @@
-package beacon
-
-import (
-	"context"
-	"sync"
-
-	"github.com/prysmaticlabs/prysm/v5/api/client/beacon/iface"
-)
-
-type NodeHealthTracker struct {
-	isHealthy  *bool
-	healthChan chan bool
-	node       iface.HealthNode
-	sync.RWMutex
-}
-
-func NewNodeHealthTracker(node iface.HealthNode) *NodeHealthTracker {
-	return &NodeHealthTracker{
-		node:       node,
-		healthChan: make(chan bool, 1),
-	}
-}
-
-// HealthUpdates provides a read-only channel for health updates.
-func (n *NodeHealthTracker) HealthUpdates() <-chan bool {
-	return n.healthChan
-}
-
-func (n *NodeHealthTracker) IsHealthy() bool {
-	n.RLock()
-	defer n.RUnlock()
-	if n.isHealthy == nil {
-		return false
-	}
-	return *n.isHealthy
-}
-
-func (n *NodeHealthTracker) CheckHealth(ctx context.Context) bool {
-	n.Lock()
-	defer n.Unlock()
-
-	newStatus := n.node.IsHealthy(ctx)
-	if n.isHealthy == nil {
-		n.isHealthy = &newStatus
-	}
-
-	isStatusChanged := newStatus != *n.isHealthy
-	if isStatusChanged {
-		// Update the health status
-		n.isHealthy = &newStatus
-		// Send the new status to the health channel, potentially overwriting the existing value
-		select {
-		case <-n.healthChan:
-			n.healthChan <- newStatus
-		default:
-			n.healthChan <- newStatus
-		}
-	}
-	return newStatus
-}
--- a/api/client/beacon/health_test.go
+++ b/api/client/beacon/health_test.go
@@ -1,112 +0,0 @@
-package beacon
-
-import (
-	"context"
-	"sync"
-	"testing"
-
-	healthTesting "github.com/prysmaticlabs/prysm/v5/api/client/beacon/testing"
-	"go.uber.org/mock/gomock"
-)
-
-func TestNodeHealth_IsHealthy(t *testing.T) {
-	tests := []struct {
-		name      string
-		isHealthy bool
-		want      bool
-	}{
-		{"initially healthy", true, true},
-		{"initially unhealthy", false, false},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			n := &NodeHealthTracker{
-				isHealthy:  &tt.isHealthy,
-				healthChan: make(chan bool, 1),
-			}
-			if got := n.IsHealthy(); got != tt.want {
-				t.Errorf("IsHealthy() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}
-
-func TestNodeHealth_UpdateNodeHealth(t *testing.T) {
-	tests := []struct {
-		name       string
-		initial    bool // Initial health status
-		newStatus  bool // Status to update to
-		shouldSend bool // Should a message be sent through the channel
-	}{
-		{"healthy to unhealthy", true, false, true},
-		{"unhealthy to healthy", false, true, true},
-		{"remain healthy", true, true, false},
-		{"remain unhealthy", false, false, false},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			client := healthTesting.NewMockHealthClient(ctrl)
-			client.EXPECT().IsHealthy(gomock.Any()).Return(tt.newStatus)
-			n := &NodeHealthTracker{
-				isHealthy:  &tt.initial,
-				node:       client,
-				healthChan: make(chan bool, 1),
-			}
-
-			s := n.CheckHealth(context.Background())
-			// Check if health status was updated
-			if s != tt.newStatus {
-				t.Errorf("UpdateNodeHealth() failed to update isHealthy from %v to %v", tt.initial, tt.newStatus)
-			}
-
-			select {
-			case status := <-n.HealthUpdates():
-				if !tt.shouldSend {
-					t.Errorf("UpdateNodeHealth() unexpectedly sent status %v to HealthCh", status)
-				} else if status != tt.newStatus {
-					t.Errorf("UpdateNodeHealth() sent wrong status %v, want %v", status, tt.newStatus)
-				}
-			default:
-				if tt.shouldSend {
-					t.Error("UpdateNodeHealth() did not send any status to HealthCh when expected")
-				}
-			}
-		})
-	}
-}
-
-func TestNodeHealth_Concurrency(t *testing.T) {
-	ctrl := gomock.NewController(t)
-	defer ctrl.Finish()
-	client := healthTesting.NewMockHealthClient(ctrl)
-	n := NewNodeHealthTracker(client)
-	var wg sync.WaitGroup
-
-	// Number of goroutines to spawn for both reading and writing
-	numGoroutines := 6
-
-	wg.Add(numGoroutines * 2) // for readers and writers
-
-	// Concurrently update health status
-	for i := 0; i < numGoroutines; i++ {
-		go func() {
-			defer wg.Done()
-			client.EXPECT().IsHealthy(gomock.Any()).Return(false).Times(1)
-			n.CheckHealth(context.Background())
-			client.EXPECT().IsHealthy(gomock.Any()).Return(true).Times(1)
-			n.CheckHealth(context.Background())
-		}()
-	}
-
-	// Concurrently read health status
-	for i := 0; i < numGoroutines; i++ {
-		go func() {
-			defer wg.Done()
-			_ = n.IsHealthy() // Just read the value
-		}()
-	}
-
-	wg.Wait() // Wait for all goroutines to finish
-}
--- a/api/client/beacon/iface/BUILD.bazel
+++ b/api/client/beacon/iface/BUILD.bazel
@@ -1,8 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["health.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon/iface",
-    visibility = ["//visibility:public"],
-)
--- a/api/client/beacon/iface/health.go
+++ b/api/client/beacon/iface/health.go
@@ -1,13 +0,0 @@
-package iface
-
-import "context"
-
-type HealthTracker interface {
-	HealthUpdates() <-chan bool
-	IsHealthy() bool
-	CheckHealth(ctx context.Context) bool
-}
-
-type HealthNode interface {
-	IsHealthy(ctx context.Context) bool
-}
--- a/api/client/beacon/log.go
+++ b/api/client/beacon/log.go
@@ -1,5 +0,0 @@
-package beacon
-
-import "github.com/sirupsen/logrus"
-
-var log = logrus.WithField("prefix", "beacon")
--- a/api/client/beacon/testing/BUILD.bazel
+++ b/api/client/beacon/testing/BUILD.bazel
@@ -1,12 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library")
-
-go_library(
-    name = "go_default_library",
-    srcs = ["mock.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/beacon/testing",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//api/client/beacon/iface:go_default_library",
-        "@org_uber_go_mock//gomock:go_default_library",
-    ],
-)
--- a/api/client/beacon/testing/mock.go
+++ b/api/client/beacon/testing/mock.go
@@ -1,59 +0,0 @@
-package testing
-
-import (
-	"context"
-	"reflect"
-	"sync"
-
-	"github.com/prysmaticlabs/prysm/v5/api/client/beacon/iface"
-	"go.uber.org/mock/gomock"
-)
-
-var (
-	_ = iface.HealthNode(&MockHealthClient{})
-)
-
-// MockHealthClient is a mock of HealthClient interface.
-type MockHealthClient struct {
-	ctrl     *gomock.Controller
-	recorder *MockHealthClientMockRecorder
-	sync.Mutex
-}
-
-// MockHealthClientMockRecorder is the mock recorder for MockHealthClient.
-type MockHealthClientMockRecorder struct {
-	mock *MockHealthClient
-}
-
-// IsHealthy mocks base method.
-func (m *MockHealthClient) IsHealthy(arg0 context.Context) bool {
-	m.Lock()
-	defer m.Unlock()
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "IsHealthy", arg0)
-	ret0, ok := ret[0].(bool)
-	if !ok {
-		return false
-	}
-	return ret0
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use.
-func (m *MockHealthClient) EXPECT() *MockHealthClientMockRecorder {
-	return m.recorder
-}
-
-// IsHealthy indicates an expected call of IsHealthy.
-func (mr *MockHealthClientMockRecorder) IsHealthy(arg0 any) *gomock.Call {
-	mr.mock.Lock()
-	defer mr.mock.Unlock()
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "IsHealthy", reflect.TypeOf((*MockHealthClient)(nil).IsHealthy), arg0)
-}
-
-// NewMockHealthClient creates a new mock instance.
-func NewMockHealthClient(ctrl *gomock.Controller) *MockHealthClient {
-	mock := &MockHealthClient{ctrl: ctrl}
-	mock.recorder = &MockHealthClientMockRecorder{mock}
-	return mock
-}
--- a/api/client/builder/BUILD.bazel
+++ b/api/client/builder/BUILD.bazel
@@ -8,11 +8,10 @@ go_library(
        "errors.go",
        "types.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/builder",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/builder",
    visibility = ["//visibility:public"],
    deps = [
-        "//api:go_default_library",
-        "//api/server/structs:go_default_library",
+        "//beacon-chain/rpc/eth/shared:go_default_library",
        "//config/fieldparams:go_default_library",
        "//consensus-types:go_default_library",
        "//consensus-types/blocks:go_default_library",
@@ -29,7 +28,6 @@ go_library(
        "@com_github_prysmaticlabs_fastssz//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
        "@io_opencensus_go//trace:go_default_library",
-        "@org_golang_google_protobuf//proto:go_default_library",
    ],
 )

@@ -42,7 +40,7 @@ go_test(
    data = glob(["testdata/**"]),
    embed = [":go_default_library"],
    deps = [
-        "//api/server/structs:go_default_library",
+        "//beacon-chain/rpc/eth/shared:go_default_library",
        "//config/fieldparams:go_default_library",
        "//config/params:go_default_library",
        "//consensus-types/blocks:go_default_library",
@@ -51,11 +49,9 @@ go_test(
        "//math:go_default_library",
        "//proto/engine/v1:go_default_library",
        "//proto/prysm/v1alpha1:go_default_library",
-        "//runtime/version:go_default_library",
        "//testing/assert:go_default_library",
        "//testing/require:go_default_library",
        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
        "@com_github_prysmaticlabs_go_bitfield//:go_default_library",
        "@com_github_sirupsen_logrus//:go_default_library",
    ],
--- a/api/client/builder/bid.go
+++ b/api/client/builder/bid.go
@@ -3,12 +3,11 @@ package builder
 import (
 	"github.com/pkg/errors"
 	ssz "github.com/prysmaticlabs/fastssz"
-	consensus_types "github.com/prysmaticlabs/prysm/v5/consensus-types"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
+	consensus_types "github.com/prysmaticlabs/prysm/v4/consensus-types"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
 )

 // SignedBid is an interface describing the method set of a signed builder bid.
@@ -23,7 +22,7 @@ type SignedBid interface {
 type Bid interface {
 	Header() (interfaces.ExecutionData, error)
 	BlobKzgCommitments() ([][]byte, error)
-	Value() primitives.Wei
+	Value() []byte
 	Pubkey() []byte
 	Version() int
 	IsNil() bool
@@ -126,8 +125,8 @@ func (b builderBid) Version() int {
 }

 // Value --
-func (b builderBid) Value() primitives.Wei {
-	return primitives.LittleEndianBytesToWei(b.p.Value)
+func (b builderBid) Value() []byte {
+	return b.p.Value
 }

 // Pubkey --
@@ -166,7 +165,7 @@ func WrappedBuilderBidCapella(p *ethpb.BuilderBidCapella) (Bid, error) {
 // Header returns the execution data interface.
 func (b builderBidCapella) Header() (interfaces.ExecutionData, error) {
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
-	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header)
+	return blocks.WrappedExecutionPayloadHeaderCapella(b.p.Header, blocks.PayloadValueToGwei(b.p.Value))
 }

 // BlobKzgCommitments --
@@ -180,8 +179,8 @@ func (b builderBidCapella) Version() int {
 }

 // Value --
-func (b builderBidCapella) Value() primitives.Wei {
-	return primitives.LittleEndianBytesToWei(b.p.Value)
+func (b builderBidCapella) Value() []byte {
+	return b.p.Value
 }

 // Pubkey --
@@ -223,8 +222,8 @@ func (b builderBidDeneb) Version() int {
 }

 // Value --
-func (b builderBidDeneb) Value() primitives.Wei {
-	return primitives.LittleEndianBytesToWei(b.p.Value)
+func (b builderBidDeneb) Value() []byte {
+	return b.p.Value
 }

 // Pubkey --
@@ -250,7 +249,7 @@ func (b builderBidDeneb) HashTreeRootWith(hh *ssz.Hasher) error {
 // Header --
 func (b builderBidDeneb) Header() (interfaces.ExecutionData, error) {
 	// We have to convert big endian to little endian because the value is coming from the execution layer.
-	return blocks.WrappedExecutionPayloadHeaderDeneb(b.p.Header)
+	return blocks.WrappedExecutionPayloadHeaderDeneb(b.p.Header, blocks.PayloadValueToGwei(b.p.Value))
 }

 // BlobKzgCommitments --
--- a/api/client/builder/client.go
+++ b/api/client/builder/client.go
@@ -13,15 +13,15 @@ import (
 	"text/template"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/monitoring/tracing"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/shared"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/monitoring/tracing"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
 	log "github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )
@@ -56,8 +56,8 @@ func (*requestLogger) observe(r *http.Request) (e error) {
 	b := bytes.NewBuffer(nil)
 	if r.Body == nil {
 		log.WithFields(log.Fields{
-			"bodyBase64": "(nil value)",
-			"url":        r.URL.String(),
+			"body-base64": "(nil value)",
+			"url":         r.URL.String(),
 		}).Info("builder http request")
 		return nil
 	}
@@ -73,8 +73,8 @@ func (*requestLogger) observe(r *http.Request) (e error) {
 	}
 	r.Body = io.NopCloser(b)
 	log.WithFields(log.Fields{
-		"bodyBase64": string(body),
-		"url":        r.URL.String(),
+		"body-base64": string(body),
+		"url":         r.URL.String(),
 	}).Info("builder http request")

 	return nil
@@ -266,9 +266,9 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 		tracing.AnnotateError(span, err)
 		return err
 	}
-	vs := make([]*structs.SignedValidatorRegistration, len(svr))
+	vs := make([]*shared.SignedValidatorRegistration, len(svr))
 	for i := 0; i < len(svr); i++ {
-		vs[i] = structs.SignedValidatorRegistrationFromConsensus(svr[i])
+		vs[i] = shared.SignedValidatorRegistrationFromConsensus(svr[i])
 	}
 	body, err := json.Marshal(vs)
 	if err != nil {
@@ -281,68 +281,127 @@ func (c *Client) RegisterValidator(ctx context.Context, svr []*ethpb.SignedValid
 	return err
 }

-var errResponseVersionMismatch = errors.New("builder API response uses a different version than requested in " + api.VersionHeader + " header")
-
 // SubmitBlindedBlock calls the builder API endpoint that binds the validator to the builder and submits the block.
 // The response is the full execution payload used to create the blinded block.
 func (c *Client) SubmitBlindedBlock(ctx context.Context, sb interfaces.ReadOnlySignedBeaconBlock) (interfaces.ExecutionData, *v1.BlobsBundle, error) {
 	if !sb.IsBlinded() {
 		return nil, nil, errNotBlinded
 	}
-
-	// massage the proto struct type data into the api response type.
-	mj, err := structs.SignedBeaconBlockMessageJsoner(sb)
-	if err != nil {
-		return nil, nil, errors.Wrap(err, "error generating blinded beacon block post request")
-	}
-
-	body, err := json.Marshal(mj)
-	if err != nil {
-		return nil, nil, errors.Wrap(err, "error marshaling blinded block post request to json")
-	}
-	postOpts := func(r *http.Request) {
-		r.Header.Add("Eth-Consensus-Version", version.String(sb.Version()))
-		r.Header.Set("Content-Type", api.JsonMediaType)
-		r.Header.Set("Accept", api.JsonMediaType)
-	}
-	// post the blinded block - the execution payload response should contain the unblinded payload, along with the
-	// blobs bundle if it is post deneb.
-	rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), postOpts)
-	if err != nil {
-		return nil, nil, errors.Wrap(err, "error posting the blinded block to the builder api")
-	}
-	// ExecutionPayloadResponse parses just the outer container and the Value key, enabling it to use the .Value
-	// key to determine which underlying data type to use to finish the unmarshaling.
-	ep := &ExecutionPayloadResponse{}
-	if err := json.Unmarshal(rb, ep); err != nil {
-		return nil, nil, errors.Wrap(err, "error unmarshaling the builder ExecutionPayloadResponse")
-	}
-	if strings.ToLower(ep.Version) != version.String(sb.Version()) {
-		return nil, nil, errors.Wrapf(errResponseVersionMismatch, "req=%s, recv=%s", strings.ToLower(ep.Version), version.String(sb.Version()))
-	}
-	// This parses the rest of the response and returns the inner data field.
-	pp, err := ep.ParsePayload()
-	if err != nil {
-		return nil, nil, errors.Wrapf(err, "failed to parse execution payload from builder with version=%s", ep.Version)
-	}
-	// Get the payload as a proto.Message so it can be wrapped as an execution payload interface.
-	pb, err := pp.PayloadProto()
-	if err != nil {
-		return nil, nil, err
-	}
-	ed, err := blocks.NewWrappedExecutionData(pb)
-	if err != nil {
-		return nil, nil, err
-	}
-	bb, ok := pp.(BlobBundler)
-	if ok {
-		bbpb, err := bb.BundleProto()
+	switch sb.Version() {
+	case version.Bellatrix:
+		psb, err := sb.PbBlindedBellatrixBlock()
 		if err != nil {
-			return nil, nil, errors.Wrapf(err, "failed to extract blobs bundle from builder response with version=%s", ep.Version)
+			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
 		}
-		return ed, bbpb, nil
+		b, err := shared.SignedBlindedBeaconBlockBellatrixFromConsensus(&ethpb.SignedBlindedBeaconBlockBellatrix{Block: psb.Block, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockBellatrix to json marshalable type")
+		}
+		body, err := json.Marshal(b)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockBellatrix value body in SubmitBlindedBlock")
+		}
+		versionOpt := func(r *http.Request) {
+			r.Header.Add("Eth-Consensus-Version", version.String(version.Bellatrix))
+		}
+		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
+
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockBellatrix to the builder api")
+		}
+		ep := &ExecPayloadResponse{}
+		if err := json.Unmarshal(rb, ep); err != nil {
+			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlock response")
+		}
+		if strings.ToLower(ep.Version) != version.String(version.Bellatrix) {
+			return nil, nil, errors.New("not a bellatrix payload")
+		}
+		p, err := ep.ToProto()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
+		}
+		payload, err := blocks.WrappedExecutionPayload(p)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
+		}
+		return payload, nil, nil
+	case version.Capella:
+		psb, err := sb.PbBlindedCapellaBlock()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
+		}
+		b, err := shared.SignedBlindedBeaconBlockCapellaFromConsensus(&ethpb.SignedBlindedBeaconBlockCapella{Block: psb.Block, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockCapella to json marshalable type")
+		}
+		body, err := json.Marshal(b)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockCapella value body in SubmitBlindedBlockCapella")
+		}
+		versionOpt := func(r *http.Request) {
+			r.Header.Add("Eth-Consensus-Version", version.String(version.Capella))
+		}
+		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
+
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockCapella to the builder api")
+		}
+		ep := &ExecPayloadResponseCapella{}
+		if err := json.Unmarshal(rb, ep); err != nil {
+			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockCapella response")
+		}
+		if strings.ToLower(ep.Version) != version.String(version.Capella) {
+			return nil, nil, errors.New("not a capella payload")
+		}
+		p, err := ep.ToProto()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
+		}
+		payload, err := blocks.WrappedExecutionPayloadCapella(p, 0)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
+		}
+		return payload, nil, nil
+	case version.Deneb:
+		psb, err := sb.PbBlindedDenebBlock()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not get protobuf block")
+		}
+		b, err := shared.SignedBlindedBeaconBlockDenebFromConsensus(&ethpb.SignedBlindedBeaconBlockDeneb{Message: psb.Message, Signature: bytesutil.SafeCopyBytes(psb.Signature)})
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not convert SignedBlindedBeaconBlockDeneb to json marshalable type")
+		}
+		body, err := json.Marshal(b)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error encoding the SignedBlindedBeaconBlockDeneb value body in SubmitBlindedBlockDeneb")
+		}
+
+		versionOpt := func(r *http.Request) {
+			r.Header.Add("Eth-Consensus-Version", version.String(version.Deneb))
+		}
+		rb, err := c.do(ctx, http.MethodPost, postBlindedBeaconBlockPath, bytes.NewBuffer(body), versionOpt)
+		if err != nil {
+			return nil, nil, errors.Wrap(err, "error posting the SignedBlindedBeaconBlockDeneb to the builder api")
+		}
+		ep := &ExecPayloadResponseDeneb{}
+		if err := json.Unmarshal(rb, ep); err != nil {
+			return nil, nil, errors.Wrap(err, "error unmarshaling the builder SubmitBlindedBlockDeneb response")
+		}
+		if strings.ToLower(ep.Version) != version.String(version.Deneb) {
+			return nil, nil, errors.New("not a deneb payload")
+		}
+		p, blobBundle, err := ep.ToProto()
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not extract proto message from payload")
+		}
+		payload, err := blocks.WrappedExecutionPayloadDeneb(p, 0)
+		if err != nil {
+			return nil, nil, errors.Wrapf(err, "could not wrap execution payload in interface")
+		}
+		return payload, blobBundle, nil
+	default:
+		return nil, nil, fmt.Errorf("unsupported block version %s", version.String(sb.Version()))
 	}
-	return ed, nil, nil
 }

 // Status asks the remote builder server for a health check. A response of 200 with an empty body is the success/healthy
--- a/api/client/builder/client_test.go
+++ b/api/client/builder/client_test.go
@@ -6,22 +6,22 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"math/big"
 	"net/http"
 	"net/url"
 	"strconv"
 	"testing"

 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/shared"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	types "github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	eth "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 	log "github.com/sirupsen/logrus"
 )

@@ -198,12 +198,12 @@ func TestClient_GetHeader(t *testing.T) {
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedTxRoot, withdrawalsRoot))
 		require.Equal(t, uint64(1), bidHeader.GasUsed())
-		// this matches the value in the testExampleHeaderResponse
-		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
-		value, err := stringToUint256(bidStr)
+		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
 		require.NoError(t, err)
-		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
-		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
+		bidValue := bytesutil.ReverseByteOrder(bid.Value())
+		require.DeepEqual(t, bidValue, value.Bytes())
+		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
 	})
 	t.Run("capella", func(t *testing.T) {
 		hc := &http.Client{
@@ -230,11 +230,12 @@ func TestClient_GetHeader(t *testing.T) {
 		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
-		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
-		value, err := stringToUint256(bidStr)
+		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
 		require.NoError(t, err)
-		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
-		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
+		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
+		bidValue := bytesutil.ReverseByteOrder(bid.Value())
+		require.DeepEqual(t, bidValue, value.Bytes())
+		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
 	})
 	t.Run("deneb", func(t *testing.T) {
 		hc := &http.Client{
@@ -261,13 +262,12 @@ func TestClient_GetHeader(t *testing.T) {
 		withdrawalsRoot, err := bidHeader.WithdrawalsRoot()
 		require.NoError(t, err)
 		require.Equal(t, true, bytes.Equal(expectedWithdrawalsRoot, withdrawalsRoot))
-
-		bidStr := "652312848583266388373324160190187140051835877600158453279131187530910662656"
-		value, err := stringToUint256(bidStr)
+		value, err := stringToUint256("652312848583266388373324160190187140051835877600158453279131187530910662656")
 		require.NoError(t, err)
-		require.Equal(t, 0, value.Int.Cmp(primitives.WeiToBigInt(bid.Value())))
-		require.Equal(t, bidStr, primitives.WeiToBigInt(bid.Value()).String())
-
+		require.Equal(t, fmt.Sprintf("%#x", value.SSZBytes()), fmt.Sprintf("%#x", bid.Value()))
+		bidValue := bytesutil.ReverseByteOrder(bid.Value())
+		require.DeepEqual(t, bidValue, value.Bytes())
+		require.DeepEqual(t, big.NewInt(0).SetBytes(bidValue), value.Int)
 		kcgCommitments, err := bid.BlobKzgCommitments()
 		require.NoError(t, err)
 		require.Equal(t, len(kcgCommitments) > 0, true)
@@ -275,24 +275,7 @@ func TestClient_GetHeader(t *testing.T) {
 			require.Equal(t, len(kcgCommitments[i]) == 48, true)
 		}
 	})
-	t.Run("deneb, too many kzg commitments", func(t *testing.T) {
-		hc := &http.Client{
-			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
-				require.Equal(t, expectedPath, r.URL.Path)
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewBufferString(testExampleHeaderResponseDenebTooManyBlobs)),
-					Request:    r.Clone(ctx),
-				}, nil
-			}),
-		}
-		c := &Client{
-			hc:      hc,
-			baseURL: &url.URL{Host: "localhost:3500", Scheme: "http"},
-		}
-		_, err := c.GetHeader(ctx, slot, bytesutil.ToBytes32(parentHash), bytesutil.ToBytes48(pubkey))
-		require.ErrorContains(t, "could not extract proto message from header: too many blob commitments: 7", err)
-	})
+
 	t.Run("unsupported version", func(t *testing.T) {
 		hc := &http.Client{
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
@@ -321,8 +304,6 @@ func TestSubmitBlindedBlock(t *testing.T) {
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
 				require.Equal(t, "bellatrix", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayload)),
@@ -349,8 +330,6 @@ func TestSubmitBlindedBlock(t *testing.T) {
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
 				require.Equal(t, "capella", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
 				return &http.Response{
 					StatusCode: http.StatusOK,
 					Body:       io.NopCloser(bytes.NewBufferString(testExampleExecutionPayloadCapella)),
@@ -380,9 +359,7 @@ func TestSubmitBlindedBlock(t *testing.T) {
 			Transport: roundtrip(func(r *http.Request) (*http.Response, error) {
 				require.Equal(t, postBlindedBeaconBlockPath, r.URL.Path)
 				require.Equal(t, "deneb", r.Header.Get("Eth-Consensus-Version"))
-				require.Equal(t, "application/json", r.Header.Get("Content-Type"))
-				require.Equal(t, "application/json", r.Header.Get("Accept"))
-				var req structs.SignedBlindedBeaconBlockDeneb
+				var req shared.SignedBlindedBeaconBlockDeneb
 				err := json.NewDecoder(r.Body).Decode(&req)
 				require.NoError(t, err)
 				block, err := req.ToConsensus()
@@ -432,10 +409,10 @@ func TestSubmitBlindedBlock(t *testing.T) {
 		sbbb, err := blocks.NewSignedBeaconBlock(testSignedBlindedBeaconBlockBellatrix(t))
 		require.NoError(t, err)
 		_, _, err = c.SubmitBlindedBlock(ctx, sbbb)
-		require.ErrorIs(t, err, errResponseVersionMismatch)
+		require.ErrorContains(t, "not a bellatrix payload", err)
 	})
 	t.Run("not blinded", func(t *testing.T) {
-		sbb, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlockBellatrix{Block: &eth.BeaconBlockBellatrix{Body: &eth.BeaconBlockBodyBellatrix{ExecutionPayload: &v1.ExecutionPayload{}}}})
+		sbb, err := blocks.NewSignedBeaconBlock(&eth.SignedBeaconBlockBellatrix{Block: &eth.BeaconBlockBellatrix{Body: &eth.BeaconBlockBodyBellatrix{}}})
 		require.NoError(t, err)
 		_, _, err = (&Client{}).SubmitBlindedBlock(ctx, sbb)
 		require.ErrorIs(t, err, errNotBlinded)
--- a/api/client/builder/testing/BUILD.bazel
+++ b/api/client/builder/testing/BUILD.bazel
@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library")
 go_library(
    name = "go_default_library",
    srcs = ["mock.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/builder/testing",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/builder/testing",
    visibility = ["//visibility:public"],
    deps = [
        "//api/client/builder:go_default_library",
--- a/api/client/builder/testing/mock.go
+++ b/api/client/builder/testing/mock.go
@@ -3,12 +3,12 @@ package testing
 import (
 	"context"

-	"github.com/prysmaticlabs/prysm/v5/api/client/builder"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/api/client/builder"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 )

 // MockClient is a mock implementation of BuilderClient.
--- a/api/client/builder/types.go
+++ b/api/client/builder/types.go
@@ -8,16 +8,12 @@ import (

 	"github.com/ethereum/go-ethereum/common/hexutil"
 	"github.com/pkg/errors"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	types "github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	"github.com/prysmaticlabs/prysm/v5/math"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"google.golang.org/protobuf/proto"
+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
+	types "github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/v4/math"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	eth "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
 )

 var errInvalidUint256 = errors.New("invalid Uint256")
@@ -48,9 +44,6 @@ func sszBytesToUint256(b []byte) (Uint256, error) {

 // SSZBytes creates an ssz-style (little-endian byte slice) representation of the Uint256.
 func (s Uint256) SSZBytes() []byte {
-	if s.Int == nil {
-		s.Int = big.NewInt(0)
-	}
 	if !math.IsValidUint256(s.Int) {
 		return []byte{}
 	}
@@ -98,9 +91,6 @@ func (s Uint256) MarshalJSON() ([]byte, error) {

 // MarshalText returns a text byte representation of Uint256.
 func (s Uint256) MarshalText() ([]byte, error) {
-	if s.Int == nil {
-		s.Int = big.NewInt(0)
-	}
 	if !math.IsValidUint256(s.Int) {
 		return nil, errors.Wrapf(errInvalidUint256, "value=%s", s.Int)
 	}
@@ -156,8 +146,6 @@ func (bb *BuilderBid) ToProto() (*eth.BuilderBid, error) {
 	}
 	return &eth.BuilderBid{
 		Header: header,
-		// Note that SSZBytes() reverses byte order for the little-endian representation.
-		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
 		Value:  bb.Value.SSZBytes(),
 		Pubkey: bb.Pubkey,
 	}, nil
@@ -277,11 +265,6 @@ func (r *ExecPayloadResponse) ToProto() (*v1.ExecutionPayload, error) {
 	return r.Data.ToProto()
 }

-func (r *ExecutionPayload) PayloadProto() (proto.Message, error) {
-	pb, err := r.ToProto()
-	return pb, err
-}
-
 // ToProto returns a ExecutionPayload Proto
 func (p *ExecutionPayload) ToProto() (*v1.ExecutionPayload, error) {
 	txs := make([][]byte, len(p.Transactions))
@@ -413,51 +396,6 @@ func FromProtoDeneb(payload *v1.ExecutionPayloadDeneb) (ExecutionPayloadDeneb, e
 	}, nil
 }

-var errInvalidTypeConversion = errors.New("unable to translate between api and foreign type")
-
-// ExecutionPayloadResponseFromData converts an ExecutionData interface value to a payload response.
-// This involves serializing the execution payload value so that the abstract payload envelope can be used.
-func ExecutionPayloadResponseFromData(ed interfaces.ExecutionData, bundle *v1.BlobsBundle) (*ExecutionPayloadResponse, error) {
-	pb := ed.Proto()
-	var data interface{}
-	var err error
-	var ver string
-	switch pbStruct := pb.(type) {
-	case *v1.ExecutionPayload:
-		ver = version.String(version.Bellatrix)
-		data, err = FromProto(pbStruct)
-		if err != nil {
-			return nil, errors.Wrap(err, "failed to convert a Bellatrix ExecutionPayload to an API response")
-		}
-	case *v1.ExecutionPayloadCapella:
-		ver = version.String(version.Capella)
-		data, err = FromProtoCapella(pbStruct)
-		if err != nil {
-			return nil, errors.Wrap(err, "failed to convert a Capella ExecutionPayload to an API response")
-		}
-	case *v1.ExecutionPayloadDeneb:
-		ver = version.String(version.Deneb)
-		payloadStruct, err := FromProtoDeneb(pbStruct)
-		if err != nil {
-			return nil, errors.Wrap(err, "failed to convert a Deneb ExecutionPayload to an API response")
-		}
-		data = &ExecutionPayloadDenebAndBlobsBundle{
-			ExecutionPayload: &payloadStruct,
-			BlobsBundle:      FromBundleProto(bundle),
-		}
-	default:
-		return nil, errInvalidTypeConversion
-	}
-	encoded, err := json.Marshal(data)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to marshal execution payload version=%s", ver)
-	}
-	return &ExecutionPayloadResponse{
-		Version: ver,
-		Data:    encoded,
-	}, nil
-}
-
 // ExecHeaderResponseCapella is the response of builder API /eth/v1/builder/header/{slot}/{parent_hash}/{pubkey} for Capella.
 type ExecHeaderResponseCapella struct {
 	Data struct {
@@ -486,8 +424,6 @@ func (bb *BuilderBidCapella) ToProto() (*eth.BuilderBidCapella, error) {
 	}
 	return &eth.BuilderBidCapella{
 		Header: header,
-		// Note that SSZBytes() reverses byte order for the little-endian representation.
-		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
 		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
 		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
 	}, nil
@@ -587,42 +523,6 @@ type ExecPayloadResponseCapella struct {
 	Data    ExecutionPayloadCapella `json:"data"`
 }

-// ExecutionPayloadResponse allows for unmarshaling just the Version field of the payload.
-// This allows it to return different ExecutionPayload types based on the version field.
-type ExecutionPayloadResponse struct {
-	Version string          `json:"version"`
-	Data    json.RawMessage `json:"data"`
-}
-
-// ParsedPayload can retrieve the underlying protobuf message for the given execution payload response.
-type ParsedPayload interface {
-	PayloadProto() (proto.Message, error)
-}
-
-// BlobBundler can retrieve the underlying blob bundle protobuf message for the given execution payload response.
-type BlobBundler interface {
-	BundleProto() (*v1.BlobsBundle, error)
-}
-
-func (r *ExecutionPayloadResponse) ParsePayload() (ParsedPayload, error) {
-	var toProto ParsedPayload
-	switch r.Version {
-	case version.String(version.Bellatrix):
-		toProto = &ExecutionPayload{}
-	case version.String(version.Capella):
-		toProto = &ExecutionPayloadCapella{}
-	case version.String(version.Deneb):
-		toProto = &ExecutionPayloadDenebAndBlobsBundle{}
-	default:
-		return nil, consensusblocks.ErrUnsupportedVersion
-	}
-
-	if err := json.Unmarshal(r.Data, toProto); err != nil {
-		return nil, errors.Wrap(err, "failed to unmarshal the response .Data field with the stated version schema")
-	}
-	return toProto, nil
-}
-
 // ExecutionPayloadCapella is a field of ExecPayloadResponseCapella.
 type ExecutionPayloadCapella struct {
 	ParentHash    hexutil.Bytes   `json:"parent_hash"`
@@ -647,11 +547,6 @@ func (r *ExecPayloadResponseCapella) ToProto() (*v1.ExecutionPayloadCapella, err
 	return r.Data.ToProto()
 }

-func (p *ExecutionPayloadCapella) PayloadProto() (proto.Message, error) {
-	pb, err := p.ToProto()
-	return pb, err
-}
-
 // ToProto returns a ExecutionPayloadCapella Proto.
 func (p *ExecutionPayloadCapella) ToProto() (*v1.ExecutionPayloadCapella, error) {
 	txs := make([][]byte, len(p.Transactions))
@@ -1013,9 +908,6 @@ func (bb *BuilderBidDeneb) ToProto() (*eth.BuilderBidDeneb, error) {
 	if err != nil {
 		return nil, err
 	}
-	if len(bb.BlobKzgCommitments) > fieldparams.MaxBlobsPerBlock {
-		return nil, fmt.Errorf("too many blob commitments: %d", len(bb.BlobKzgCommitments))
-	}
 	kzgCommitments := make([][]byte, len(bb.BlobKzgCommitments))
 	for i, commit := range bb.BlobKzgCommitments {
 		if len(commit) != fieldparams.BLSPubkeyLength {
@@ -1026,10 +918,8 @@ func (bb *BuilderBidDeneb) ToProto() (*eth.BuilderBidDeneb, error) {
 	return &eth.BuilderBidDeneb{
 		Header:             header,
 		BlobKzgCommitments: kzgCommitments,
-		// Note that SSZBytes() reverses byte order for the little-endian representation.
-		// Uint256.Bytes() is big-endian, SSZBytes takes this value and reverses it.
-		Value:  bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
-		Pubkey: bytesutil.SafeCopyBytes(bb.Pubkey),
+		Value:              bytesutil.SafeCopyBytes(bb.Value.SSZBytes()),
+		Pubkey:             bytesutil.SafeCopyBytes(bb.Pubkey),
 	}, nil
 }

@@ -1235,12 +1125,6 @@ func (r *ExecPayloadResponseDeneb) ToProto() (*v1.ExecutionPayloadDeneb, *v1.Blo
 	if r.Data == nil {
 		return nil, nil, errors.New("data field in response is empty")
 	}
-	if r.Data.ExecutionPayload == nil {
-		return nil, nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload")
-	}
-	if r.Data.BlobsBundle == nil {
-		return nil, nil, errors.Wrap(consensusblocks.ErrNilObject, "nil blobs bundle")
-	}
 	payload, err := r.Data.ExecutionPayload.ToProto()
 	if err != nil {
 		return nil, nil, err
@@ -1252,26 +1136,8 @@ func (r *ExecPayloadResponseDeneb) ToProto() (*v1.ExecutionPayloadDeneb, *v1.Blo
 	return payload, bundle, nil
 }

-func (r *ExecutionPayloadDenebAndBlobsBundle) PayloadProto() (proto.Message, error) {
-	if r.ExecutionPayload == nil {
-		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload in combined deneb payload")
-	}
-	pb, err := r.ExecutionPayload.ToProto()
-	return pb, err
-}
-
-func (r *ExecutionPayloadDenebAndBlobsBundle) BundleProto() (*v1.BlobsBundle, error) {
-	if r.BlobsBundle == nil {
-		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil blobs bundle")
-	}
-	return r.BlobsBundle.ToProto()
-}
-
 // ToProto returns the ExecutionPayloadDeneb Proto.
 func (p *ExecutionPayloadDeneb) ToProto() (*v1.ExecutionPayloadDeneb, error) {
-	if p == nil {
-		return nil, errors.Wrap(consensusblocks.ErrNilObject, "nil execution payload")
-	}
 	txs := make([][]byte, len(p.Transactions))
 	for i := range p.Transactions {
 		txs[i] = bytesutil.SafeCopyBytes(p.Transactions[i])
--- a/api/client/builder/types_test.go
+++ b/api/client/builder/types_test.go
@@ -12,17 +12,14 @@ import (
 	"testing"

 	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
-	"github.com/prysmaticlabs/prysm/v5/api/server/structs"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/math"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/rpc/eth/shared"
+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/v4/math"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	eth "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func ezDecode(t *testing.T, s string) []byte {
@@ -41,7 +38,7 @@ func TestSignedValidatorRegistration_MarshalJSON(t *testing.T) {
 		},
 		Signature: make([]byte, 96),
 	}
-	a := structs.SignedValidatorRegistrationFromConsensus(svr)
+	a := shared.SignedValidatorRegistrationFromConsensus(svr)
 	je, err := json.Marshal(a)
 	require.NoError(t, err)
 	// decode with a struct w/ plain strings so we can check the string encoding of the hex fields
@@ -58,7 +55,7 @@ func TestSignedValidatorRegistration_MarshalJSON(t *testing.T) {
 	require.Equal(t, "0x000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000", un.Message.Pubkey)

 	t.Run("roundtrip", func(t *testing.T) {
-		b := &structs.SignedValidatorRegistration{}
+		b := &shared.SignedValidatorRegistration{}
 		if err := json.Unmarshal(je, b); err != nil {
 			require.NoError(t, err)
 		}
@@ -212,39 +209,6 @@ var testExampleHeaderResponseUnknownVersion = `{
  }
 }`

-var testExampleHeaderResponseDenebTooManyBlobs = `{
-  "version": "deneb",
-  "data": {
-    "message": {
-      "header": {
-        "parent_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "fee_recipient": "0xabcf8e0d4e9587369b2301d0790347320302cc09",
-        "state_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "receipts_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "logs_bloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
-        "prev_randao": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "block_number": "1",
-        "gas_limit": "1",
-        "gas_used": "1",
-        "timestamp": "1",
-        "extra_data": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "base_fee_per_gas": "452312848583266388373324160190187140051835877600158453279131187530910662656",
-		"block_hash": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "transactions_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-        "withdrawals_root": "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2",
-		"blob_gas_used": "1",	
-		"excess_blob_gas": "2"	
-      },
-      "blob_kzg_commitments": [
-          "","","","","","",""
-	  ],
-      "value": "652312848583266388373324160190187140051835877600158453279131187530910662656",
-      "pubkey": "0x93247f2209abcacf57b75a51dafae777f9dd38bc7053d1af526f220a7489a6d3a2753e5f3e8b1cfe39b56f43611df74a"
-    },
-    "signature": "0x1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505cc411d61252fb6cb3fa0017b679f8bb2305b26a285fa2737f175668d0dff91cc1b66ac1fb663c9bc59509846d6ec05345bd908eda73e670af888da41af171505"
-  }
-}`
-
 func TestExecutionHeaderResponseUnmarshal(t *testing.T) {
 	hr := &ExecHeaderResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testExampleHeaderResponse), hr))
@@ -1603,6 +1567,7 @@ func TestBuilderBidUnmarshalUint256(t *testing.T) {
 	require.NoError(t, expectedValue.UnmarshalText([]byte(base10)))
 	r := &ExecHeaderResponse{}
 	require.NoError(t, json.Unmarshal([]byte(testBuilderBid), r))
+	//require.Equal(t, expectedValue, r.Data.Message.Value)
 	marshaled := r.Data.Message.Value.String()
 	require.Equal(t, base10, marshaled)
 	require.Equal(t, 0, expectedValue.Cmp(r.Data.Message.Value.Int))
@@ -1720,7 +1685,7 @@ func TestUint256UnmarshalTooBig(t *testing.T) {
 func TestMarshalBlindedBeaconBlockBodyBellatrix(t *testing.T) {
 	expected, err := os.ReadFile("testdata/blinded-block.json")
 	require.NoError(t, err)
-	b, err := structs.BlindedBeaconBlockBellatrixFromConsensus(&eth.BlindedBeaconBlockBellatrix{
+	b, err := shared.BlindedBeaconBlockBellatrixFromConsensus(&eth.BlindedBeaconBlockBellatrix{
 		Slot:          1,
 		ProposerIndex: 1,
 		ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -1750,7 +1715,7 @@ func TestMarshalBlindedBeaconBlockBodyBellatrix(t *testing.T) {
 func TestMarshalBlindedBeaconBlockBodyCapella(t *testing.T) {
 	expected, err := os.ReadFile("testdata/blinded-block-capella.json")
 	require.NoError(t, err)
-	b, err := structs.BlindedBeaconBlockCapellaFromConsensus(&eth.BlindedBeaconBlockCapella{
+	b, err := shared.BlindedBeaconBlockCapellaFromConsensus(&eth.BlindedBeaconBlockCapella{
 		Slot:          1,
 		ProposerIndex: 1,
 		ParentRoot:    ezDecode(t, "0xcf8e0d4e9587369b2301d0790347320302cc0943d5a1884560367e8208d920f2"),
@@ -1909,41 +1874,3 @@ func TestErrorMessage_non200Err(t *testing.T) {
 		})
 	}
 }
-
-func TestEmptyResponseBody(t *testing.T) {
-	t.Run("empty buffer", func(t *testing.T) {
-		var b []byte
-		r := &ExecutionPayloadResponse{}
-		err := json.Unmarshal(b, r)
-		var syntaxError *json.SyntaxError
-		ok := errors.As(err, &syntaxError)
-		require.Equal(t, true, ok)
-	})
-	t.Run("empty object", func(t *testing.T) {
-		empty := []byte("{}")
-		emptyResponse := &ExecutionPayloadResponse{}
-		require.NoError(t, json.Unmarshal(empty, emptyResponse))
-		_, err := emptyResponse.ParsePayload()
-		require.ErrorIs(t, err, consensusblocks.ErrUnsupportedVersion)
-	})
-	versions := []int{version.Bellatrix, version.Capella, version.Deneb}
-	for i := range versions {
-		vstr := version.String(versions[i])
-		t.Run("populated version without payload"+vstr, func(t *testing.T) {
-			in := &ExecutionPayloadResponse{Version: vstr}
-			encoded, err := json.Marshal(in)
-			require.NoError(t, err)
-			epr := &ExecutionPayloadResponse{}
-			require.NoError(t, json.Unmarshal(encoded, epr))
-			pp, err := epr.ParsePayload()
-			require.NoError(t, err)
-			pb, err := pp.PayloadProto()
-			if err == nil {
-				require.NoError(t, err)
-				require.Equal(t, false, pb == nil)
-			} else {
-				require.ErrorIs(t, err, consensusblocks.ErrNilObject)
-			}
-		})
-	}
-}
--- a/api/client/client_test.go
+++ b/api/client/client_test.go
@@ -4,7 +4,7 @@ import (
 	"net/url"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestValidHostname(t *testing.T) {
--- a/api/client/errors.go
+++ b/api/client/errors.go
@@ -21,9 +21,6 @@ var ErrNotFound = errors.Wrap(ErrNotOK, "recv 404 NotFound response from API")
 // ErrInvalidNodeVersion indicates that the /eth/v1/node/version API response format was not recognized.
 var ErrInvalidNodeVersion = errors.New("invalid node version response")

-// ErrConnectionIssue represents a connection problem.
-var ErrConnectionIssue = errors.New("could not connect")
-
 // Non200Err is a function that parses an HTTP response to handle responses that are not 200 with a formatted error.
 func Non200Err(response *http.Response) error {
 	bodyBytes, err := io.ReadAll(response.Body)
--- a/api/client/event/BUILD.bazel
+++ b/api/client/event/BUILD.bazel
@@ -1,30 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "event_stream.go",
-        "utils.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/event",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//api:go_default_library",
-        "//api/client:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "event_stream_test.go",
-        "utils_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//testing/require:go_default_library",
-        "@com_github_sirupsen_logrus//:go_default_library",
-    ],
-)
--- a/api/client/event/event_stream.go
+++ b/api/client/event/event_stream.go
@@ -1,150 +0,0 @@
-package event
-
-import (
-	"bufio"
-	"context"
-	"net/http"
-	"net/url"
-	"strings"
-
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	log "github.com/sirupsen/logrus"
-)
-
-const (
-	EventHead                        = "head"
-	EventBlock                       = "block"
-	EventAttestation                 = "attestation"
-	EventVoluntaryExit               = "voluntary_exit"
-	EventBlsToExecutionChange        = "bls_to_execution_change"
-	EventProposerSlashing            = "proposer_slashing"
-	EventAttesterSlashing            = "attester_slashing"
-	EventFinalizedCheckpoint         = "finalized_checkpoint"
-	EventChainReorg                  = "chain_reorg"
-	EventContributionAndProof        = "contribution_and_proof"
-	EventLightClientFinalityUpdate   = "light_client_finality_update"
-	EventLightClientOptimisticUpdate = "light_client_optimistic_update"
-	EventPayloadAttributes           = "payload_attributes"
-	EventBlobSidecar                 = "blob_sidecar"
-	EventError                       = "error"
-	EventConnectionError             = "connection_error"
-)
-
-var (
-	_ = EventStreamClient(&EventStream{})
-)
-
-var DefaultEventTopics = []string{EventHead}
-
-type EventStreamClient interface {
-	Subscribe(eventsChannel chan<- *Event)
-}
-
-type Event struct {
-	EventType string
-	Data      []byte
-}
-
-// EventStream is responsible for subscribing to the Beacon API events endpoint
-// and dispatching received events to subscribers.
-type EventStream struct {
-	ctx        context.Context
-	httpClient *http.Client
-	host       string
-	topics     []string
-}
-
-func NewEventStream(ctx context.Context, httpClient *http.Client, host string, topics []string) (*EventStream, error) {
-	// Check if the host is a valid URL
-	_, err := url.ParseRequestURI(host)
-	if err != nil {
-		return nil, err
-	}
-	if len(topics) == 0 {
-		return nil, errors.New("no topics provided")
-	}
-
-	return &EventStream{
-		ctx:        ctx,
-		httpClient: httpClient,
-		host:       host,
-		topics:     topics,
-	}, nil
-}
-
-func (h *EventStream) Subscribe(eventsChannel chan<- *Event) {
-	allTopics := strings.Join(h.topics, ",")
-	log.WithField("topics", allTopics).Info("Listening to Beacon API events")
-	fullUrl := h.host + "/eth/v1/events?topics=" + allTopics
-	req, err := http.NewRequestWithContext(h.ctx, http.MethodGet, fullUrl, nil)
-	if err != nil {
-		eventsChannel <- &Event{
-			EventType: EventConnectionError,
-			Data:      []byte(errors.Wrap(err, "failed to create HTTP request").Error()),
-		}
-	}
-	req.Header.Set("Accept", api.EventStreamMediaType)
-	req.Header.Set("Connection", api.KeepAlive)
-	resp, err := h.httpClient.Do(req)
-	if err != nil {
-		eventsChannel <- &Event{
-			EventType: EventConnectionError,
-			Data:      []byte(errors.Wrap(err, client.ErrConnectionIssue.Error()).Error()),
-		}
-	}
-
-	defer func() {
-		if closeErr := resp.Body.Close(); closeErr != nil {
-			log.WithError(closeErr).Error("Failed to close events response body")
-		}
-	}()
-	// Create a new scanner to read lines from the response body
-	scanner := bufio.NewScanner(resp.Body)
-	// Set the split function for the scanning operation
-	scanner.Split(scanLinesWithCarriage)
-
-	var eventType, data string // Variables to store event type and data
-
-	// Iterate over lines of the event stream
-	for scanner.Scan() {
-		select {
-		case <-h.ctx.Done():
-			log.Info("Context canceled, stopping event stream")
-			close(eventsChannel)
-			return
-		default:
-			line := scanner.Text()
-			// Handle the event based on your specific format
-			if line == "" {
-				// Empty line indicates the end of an event
-				if eventType != "" && data != "" {
-					// Process the event when both eventType and data are set
-					eventsChannel <- &Event{EventType: eventType, Data: []byte(data)}
-				}
-
-				// Reset eventType and data for the next event
-				eventType, data = "", ""
-				continue
-			}
-			et, ok := strings.CutPrefix(line, "event: ")
-			if ok {
-				// Extract event type from the "event" field
-				eventType = et
-			}
-			d, ok := strings.CutPrefix(line, "data: ")
-			if ok {
-				// Extract data from the "data" field
-				data = d
-			}
-		}
-	}
-
-	if err := scanner.Err(); err != nil {
-		eventsChannel <- &Event{
-			EventType: EventConnectionError,
-			Data:      []byte(errors.Wrap(err, errors.Wrap(client.ErrConnectionIssue, "scanner failed").Error()).Error()),
-		}
-	}
-}
--- a/api/client/event/event_stream_test.go
+++ b/api/client/event/event_stream_test.go
@@ -1,81 +0,0 @@
-package event
-
-import (
-	"context"
-	"fmt"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-	"time"
-
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	log "github.com/sirupsen/logrus"
-)
-
-func TestNewEventStream(t *testing.T) {
-	validURL := "http://localhost:8080"
-	invalidURL := "://invalid"
-	topics := []string{"topic1", "topic2"}
-
-	tests := []struct {
-		name    string
-		host    string
-		topics  []string
-		wantErr bool
-	}{
-		{"Valid input", validURL, topics, false},
-		{"Invalid URL", invalidURL, topics, true},
-		{"No topics", validURL, []string{}, true},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			_, err := NewEventStream(context.Background(), &http.Client{}, tt.host, tt.topics)
-			if (err != nil) != tt.wantErr {
-				t.Errorf("NewEventStream() error = %v, wantErr %v", err, tt.wantErr)
-			}
-		})
-	}
-}
-
-func TestEventStream(t *testing.T) {
-	mux := http.NewServeMux()
-	mux.HandleFunc("/eth/v1/events", func(w http.ResponseWriter, r *http.Request) {
-		flusher, ok := w.(http.Flusher)
-		require.Equal(t, true, ok)
-		for i := 1; i <= 3; i++ {
-			events := [3]string{"event: head\ndata: data%d\n\n", "event: head\rdata: data%d\r\r", "event: head\r\ndata: data%d\r\n\r\n"}
-			_, err := fmt.Fprintf(w, events[i-1], i)
-			require.NoError(t, err)
-			flusher.Flush()                    // Trigger flush to simulate streaming data
-			time.Sleep(100 * time.Millisecond) // Simulate delay between events
-		}
-	})
-	server := httptest.NewServer(mux)
-	defer server.Close()
-
-	topics := []string{"head"}
-	eventsChannel := make(chan *Event, 1)
-	stream, err := NewEventStream(context.Background(), http.DefaultClient, server.URL, topics)
-	require.NoError(t, err)
-	go stream.Subscribe(eventsChannel)
-
-	// Collect events
-	var events []*Event
-
-	for len(events) != 3 {
-		select {
-		case event := <-eventsChannel:
-			log.Info(event)
-			events = append(events, event)
-		}
-	}
-
-	// Assertions to verify the events content
-	expectedData := []string{"data1", "data2", "data3"}
-	for i, event := range events {
-		if string(event.Data) != expectedData[i] {
-			t.Errorf("Expected event data %q, got %q", expectedData[i], string(event.Data))
-		}
-	}
-}
--- a/api/client/event/utils.go
+++ b/api/client/event/utils.go
@@ -1,36 +0,0 @@
-package event
-
-import (
-	"bytes"
-)
-
-// adapted from ScanLines in scan.go to handle carriage return characters as separators
-func scanLinesWithCarriage(data []byte, atEOF bool) (advance int, token []byte, err error) {
-	if atEOF && len(data) == 0 {
-		return 0, nil, nil
-	}
-	if i, j := bytes.IndexByte(data, '\n'), bytes.IndexByte(data, '\r'); i >= 0 || j >= 0 {
-		in := i
-		// Select the first index of \n or \r or the second index of \r if it is followed by \n
-		if i < 0 || (i > j && i != j+1 && j >= 0) {
-			in = j
-		}
-
-		// We have a full newline-terminated line.
-		return in + 1, dropCR(data[0:in]), nil
-	}
-	// If we're at EOF, we have a final, non-terminated line. Return it.
-	if atEOF {
-		return len(data), dropCR(data), nil
-	}
-	// Request more data.
-	return 0, nil, nil
-}
-
-// dropCR drops a terminal \r from the data.
-func dropCR(data []byte) []byte {
-	if len(data) > 0 && data[len(data)-1] == '\r' {
-		return data[0 : len(data)-1]
-	}
-	return data
-}
--- a/api/client/event/utils_test.go
+++ b/api/client/event/utils_test.go
@@ -1,97 +0,0 @@
-package event
-
-import (
-	"bufio"
-	"bytes"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-)
-
-func TestScanLinesWithCarriage(t *testing.T) {
-	testCases := []struct {
-		name     string
-		input    string
-		expected []string
-	}{
-		{
-			name:     "LF line endings",
-			input:    "line1\nline2\nline3",
-			expected: []string{"line1", "line2", "line3"},
-		},
-		{
-			name:     "CR line endings",
-			input:    "line1\rline2\rline3",
-			expected: []string{"line1", "line2", "line3"},
-		},
-		{
-			name:     "CRLF line endings",
-			input:    "line1\r\nline2\r\nline3",
-			expected: []string{"line1", "line2", "line3"},
-		},
-		{
-			name:     "Mixed line endings",
-			input:    "line1\nline2\rline3\r\nline4",
-			expected: []string{"line1", "line2", "line3", "line4"},
-		},
-		{
-			name:     "Empty lines",
-			input:    "line1\n\nline2\r\rline3",
-			expected: []string{"line1", "", "line2", "", "line3"},
-		},
-		{
-			name:     "Empty lines 2",
-			input:    "line1\n\rline2\n\rline3",
-			expected: []string{"line1", "", "line2", "", "line3"},
-		},
-		{
-			name:     "No line endings",
-			input:    "single line without ending",
-			expected: []string{"single line without ending"},
-		},
-	}
-
-	for _, tc := range testCases {
-		t.Run(tc.name, func(t *testing.T) {
-			scanner := bufio.NewScanner(bytes.NewReader([]byte(tc.input)))
-			scanner.Split(scanLinesWithCarriage)
-
-			var lines []string
-			for scanner.Scan() {
-				lines = append(lines, scanner.Text())
-			}
-
-			require.NoError(t, scanner.Err())
-			require.Equal(t, len(tc.expected), len(lines), "Number of lines does not match")
-			for i, line := range lines {
-				require.Equal(t, tc.expected[i], line, "Line %d does not match", i)
-			}
-		})
-	}
-}
-
-// TestScanLinesWithCarriageEdgeCases tests edge cases and potential error scenarios
-func TestScanLinesWithCarriageEdgeCases(t *testing.T) {
-	t.Run("Empty input", func(t *testing.T) {
-		scanner := bufio.NewScanner(bytes.NewReader([]byte("")))
-		scanner.Split(scanLinesWithCarriage)
-		require.Equal(t, scanner.Scan(), false)
-		require.NoError(t, scanner.Err())
-	})
-
-	t.Run("Very long line", func(t *testing.T) {
-		longLine := bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize+1)
-		scanner := bufio.NewScanner(bytes.NewReader(longLine))
-		scanner.Split(scanLinesWithCarriage)
-		require.Equal(t, scanner.Scan(), false)
-		require.NotNil(t, scanner.Err())
-	})
-
-	t.Run("Line ending at max token size", func(t *testing.T) {
-		input := append(bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize-1), '\n')
-		scanner := bufio.NewScanner(bytes.NewReader(input))
-		scanner.Split(scanLinesWithCarriage)
-		require.Equal(t, scanner.Scan(), true)
-		require.Equal(t, string(bytes.Repeat([]byte("a"), bufio.MaxScanTokenSize-1)), scanner.Text())
-	})
-}
--- a/api/client/validator/BUILD.bazel
+++ b/api/client/validator/BUILD.bazel
@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library")
 go_library(
    name = "go_default_library",
    srcs = ["client.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/client/validator",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/client/validator",
    visibility = ["//visibility:public"],
    deps = [
        "//api/client:go_default_library",
--- a/api/client/validator/client.go
+++ b/api/client/validator/client.go
@@ -7,8 +7,8 @@ import (
 	"strings"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/client"
-	"github.com/prysmaticlabs/prysm/v5/validator/rpc"
+	"github.com/prysmaticlabs/prysm/v4/api/client"
+	"github.com/prysmaticlabs/prysm/v4/validator/rpc"
 )

 const (
--- a/api/constants.go
+++ b/api/constants.go
@@ -1,9 +1,3 @@
 package api

-const (
-	WebUrlPrefix        = "/v2/validator/"
-	WebApiUrlPrefix     = "/api/v2/validator/"
-	KeymanagerApiPrefix = "/eth/v1"
-	SystemLogsPrefix    = "health/logs"
-	AuthTokenFileName   = "auth-token"
-)
+const WebUrlPrefix = "/v2/validator/"
--- a/api/gateway/BUILD.bazel
+++ b/api/gateway/BUILD.bazel
@@ -8,13 +8,13 @@ go_library(
        "modifiers.go",
        "options.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/gateway",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/gateway",
    visibility = [
        "//beacon-chain:__subpackages__",
        "//validator:__subpackages__",
    ],
    deps = [
-        "//api/server/middleware:go_default_library",
+        "//api/server:go_default_library",
        "//runtime:go_default_library",
        "@com_github_gorilla_mux//:go_default_library",
        "@com_github_grpc_ecosystem_grpc_gateway_v2//runtime:go_default_library",
--- a/api/gateway/gateway.go
+++ b/api/gateway/gateway.go
@@ -11,8 +11,8 @@ import (
 	"github.com/gorilla/mux"
 	gwruntime "github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/api/server/middleware"
-	"github.com/prysmaticlabs/prysm/v5/runtime"
+	"github.com/prysmaticlabs/prysm/v4/api/server"
+	"github.com/prysmaticlabs/prysm/v4/runtime"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
@@ -104,7 +104,7 @@ func (g *Gateway) Start() {
 		}
 	}

-	corsMux := middleware.CorsHandler(g.cfg.allowedOrigins).Middleware(g.cfg.router)
+	corsMux := server.CorsHandler(g.cfg.allowedOrigins).Middleware(g.cfg.router)

 	if g.cfg.muxHandler != nil {
 		g.cfg.router.PathPrefix("/").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
--- a/api/gateway/gateway_test.go
+++ b/api/gateway/gateway_test.go
@@ -10,9 +10,9 @@ import (
 	"testing"

 	"github.com/gorilla/mux"
-	"github.com/prysmaticlabs/prysm/v5/cmd/beacon-chain/flags"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/cmd/beacon-chain/flags"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 	"github.com/urfave/cli/v2"
 )
--- a/api/grpc/BUILD.bazel
+++ b/api/grpc/BUILD.bazel
@@ -6,7 +6,7 @@ go_library(
        "grpcutils.go",
        "parameters.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/grpc",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/grpc",
    visibility = ["//visibility:public"],
    deps = [
        "@com_github_sirupsen_logrus//:go_default_library",
--- a/api/grpc/grpcutils_test.go
+++ b/api/grpc/grpcutils_test.go
@@ -7,8 +7,8 @@ import (
 	"testing"

 	"github.com/grpc-ecosystem/grpc-gateway/v2/runtime"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/metadata"
--- a/api/headers.go
+++ b/api/headers.go
@@ -7,6 +7,4 @@ const (
 	ConsensusBlockValueHeader     = "Eth-Consensus-Block-Value"
 	JsonMediaType                 = "application/json"
 	OctetStreamMediaType          = "application/octet-stream"
-	EventStreamMediaType          = "text/event-stream"
-	KeepAlive                     = "keep-alive"
 )
--- a/api/jwt.go
+++ b/api/jwt.go
@@ -1,32 +0,0 @@
-package api
-
-import (
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/crypto/rand"
-)
-
-// GenerateRandomHexString generates a random hex string that follows the standards for jwt token
-// used for beacon node -> execution client
-// used for web client -> validator client
-func GenerateRandomHexString() (string, error) {
-	secret := make([]byte, 32)
-	randGen := rand.NewGenerator()
-	n, err := randGen.Read(secret)
-	if err != nil {
-		return "", err
-	} else if n != 32 {
-		return "", errors.New("rand: unexpected length")
-	}
-	return hexutil.Encode(secret), nil
-}
-
-// ValidateAuthToken validating auth token for web
-func ValidateAuthToken(token string) error {
-	b, err := hexutil.Decode(token)
-	// token should be hex-encoded and at least 256 bits
-	if err != nil || len(b) < 32 {
-		return errors.New("invalid auth token: token should be hex-encoded and at least 256 bits")
-	}
-	return nil
-}
--- a/api/jwt_test.go
+++ b/api/jwt_test.go
@@ -1,13 +0,0 @@
-package api
-
-import (
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-)
-
-func TestGenerateRandomHexString(t *testing.T) {
-	token, err := GenerateRandomHexString()
-	require.NoError(t, err)
-	require.NoError(t, ValidateAuthToken(token))
-}
--- a/api/pagination/BUILD.bazel
+++ b/api/pagination/BUILD.bazel
@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = ["pagination.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/pagination",
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/pagination",
    visibility = ["//visibility:public"],
    deps = [
        "//config/params:go_default_library",
--- a/api/pagination/pagination.go
+++ b/api/pagination/pagination.go
@@ -6,7 +6,7 @@ import (
 	"strconv"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
 )

 // StartAndEndPage takes in the requested page token, wanted page size, total page size.
--- a/api/pagination/pagination_test.go
+++ b/api/pagination/pagination_test.go
@@ -3,9 +3,9 @@ package pagination_test
 import (
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/api/pagination"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/api/pagination"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestStartAndEndPage(t *testing.T) {
--- a/api/server/BUILD.bazel
+++ b/api/server/BUILD.bazel
@@ -2,14 +2,29 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")

 go_library(
    name = "go_default_library",
-    srcs = ["error.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/server",
+    srcs = [
+        "error.go",
+        "middleware.go",
+        "util.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/v4/api/server",
    visibility = ["//visibility:public"],
+    deps = [
+        "@com_github_gorilla_mux//:go_default_library",
+        "@com_github_rs_cors//:go_default_library",
+    ],
 )

 go_test(
    name = "go_default_test",
-    srcs = ["error_test.go"],
+    srcs = [
+        "error_test.go",
+        "middleware_test.go",
+        "util_test.go",
+    ],
    embed = [":go_default_library"],
-    deps = ["//testing/assert:go_default_library"],
+    deps = [
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+    ],
 )
--- a/api/server/error.go
+++ b/api/server/error.go
@@ -1,7 +1,6 @@
 package server

 import (
-	"errors"
 	"fmt"
 	"strings"
 )
@@ -16,8 +15,7 @@ type DecodeError struct {
 // NewDecodeError wraps an error (either the initial decoding error or another DecodeError).
 // The current field that failed decoding must be passed in.
 func NewDecodeError(err error, field string) *DecodeError {
-	var de *DecodeError
-	ok := errors.As(err, &de)
+	de, ok := err.(*DecodeError)
 	if ok {
 		return &DecodeError{path: append([]string{field}, de.path...), err: de.err}
 	}
--- a/api/server/error_test.go
+++ b/api/server/error_test.go
@@ -4,7 +4,7 @@ import (
 	"errors"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
 )

 func TestDecodeError(t *testing.T) {
--- a/api/server/middleware.go
+++ b/api/server/middleware.go
@@ -0,0 +1,32 @@
+package server
+
+import (
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/rs/cors"
+)
+
+// NormalizeQueryValuesHandler normalizes an input query of "key=value1,value2,value3" to "key=value1&key=value2&key=value3"
+func NormalizeQueryValuesHandler(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		query := r.URL.Query()
+		NormalizeQueryValues(query)
+		r.URL.RawQuery = query.Encode()
+
+		next.ServeHTTP(w, r)
+	})
+}
+
+// CorsHandler sets the cors settings on api endpoints
+func CorsHandler(allowOrigins []string) mux.MiddlewareFunc {
+	c := cors.New(cors.Options{
+		AllowedOrigins:   allowOrigins,
+		AllowedMethods:   []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodOptions},
+		AllowCredentials: true,
+		MaxAge:           600,
+		AllowedHeaders:   []string{"*"},
+	})
+
+	return c.Handler
+}
--- a/api/server/middleware/BUILD.bazel
+++ b/api/server/middleware/BUILD.bazel
@@ -1,29 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "middleware.go",
-        "util.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/server/middleware",
-    visibility = ["//visibility:public"],
-    deps = [
-        "@com_github_gorilla_mux//:go_default_library",
-        "@com_github_rs_cors//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = [
-        "middleware_test.go",
-        "util_test.go",
-    ],
-    embed = [":go_default_library"],
-    deps = [
-        "//api:go_default_library",
-        "//testing/assert:go_default_library",
-        "//testing/require:go_default_library",
-    ],
-)
--- a/api/server/middleware/middleware.go
+++ b/api/server/middleware/middleware.go
@@ -1,112 +0,0 @@
-package middleware
-
-import (
-	"fmt"
-	"net/http"
-	"strings"
-
-	"github.com/gorilla/mux"
-	"github.com/rs/cors"
-)
-
-// NormalizeQueryValuesHandler normalizes an input query of "key=value1,value2,value3" to "key=value1&key=value2&key=value3"
-func NormalizeQueryValuesHandler(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		query := r.URL.Query()
-		NormalizeQueryValues(query)
-		r.URL.RawQuery = query.Encode()
-
-		next.ServeHTTP(w, r)
-	})
-}
-
-// CorsHandler sets the cors settings on api endpoints
-func CorsHandler(allowOrigins []string) mux.MiddlewareFunc {
-	c := cors.New(cors.Options{
-		AllowedOrigins:   allowOrigins,
-		AllowedMethods:   []string{http.MethodPost, http.MethodGet, http.MethodDelete, http.MethodOptions},
-		AllowCredentials: true,
-		MaxAge:           600,
-		AllowedHeaders:   []string{"*"},
-	})
-
-	return c.Handler
-}
-
-// ContentTypeHandler checks request for the appropriate media types otherwise returning a http.StatusUnsupportedMediaType error
-func ContentTypeHandler(acceptedMediaTypes []string) mux.MiddlewareFunc {
-	return func(next http.Handler) http.Handler {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			// skip the GET request
-			if r.Method == http.MethodGet {
-				next.ServeHTTP(w, r)
-				return
-			}
-			contentType := r.Header.Get("Content-Type")
-			if contentType == "" {
-				http.Error(w, "Content-Type header is missing", http.StatusUnsupportedMediaType)
-				return
-			}
-
-			accepted := false
-			for _, acceptedType := range acceptedMediaTypes {
-				if strings.Contains(strings.TrimSpace(contentType), strings.TrimSpace(acceptedType)) {
-					accepted = true
-					break
-				}
-			}
-
-			if !accepted {
-				http.Error(w, fmt.Sprintf("Unsupported media type: %s", contentType), http.StatusUnsupportedMediaType)
-				return
-			}
-
-			next.ServeHTTP(w, r)
-		})
-	}
-}
-
-// AcceptHeaderHandler checks if the client's response preference is handled
-func AcceptHeaderHandler(serverAcceptedTypes []string) mux.MiddlewareFunc {
-	return func(next http.Handler) http.Handler {
-		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			acceptHeader := r.Header.Get("Accept")
-			// header is optional and should skip if not provided
-			if acceptHeader == "" {
-				next.ServeHTTP(w, r)
-				return
-			}
-
-			accepted := false
-			acceptTypes := strings.Split(acceptHeader, ",")
-			// follows rules defined in https://datatracker.ietf.org/doc/html/rfc2616#section-14.1
-			for _, acceptType := range acceptTypes {
-				acceptType = strings.TrimSpace(acceptType)
-				if acceptType == "*/*" {
-					accepted = true
-					break
-				}
-				for _, serverAcceptedType := range serverAcceptedTypes {
-					if strings.HasPrefix(acceptType, serverAcceptedType) {
-						accepted = true
-						break
-					}
-					if acceptType != "/*" && strings.HasSuffix(acceptType, "/*") && strings.HasPrefix(serverAcceptedType, acceptType[:len(acceptType)-2]) {
-						accepted = true
-						break
-					}
-				}
-				if accepted {
-					break
-				}
-			}
-
-			if !accepted {
-				http.Error(w, fmt.Sprintf("Not Acceptable: %s", acceptHeader), http.StatusNotAcceptable)
-				return
-			}
-
-			next.ServeHTTP(w, r)
-		})
-	}
-}
--- a/api/server/middleware/middleware_test.go
+++ b/api/server/middleware/middleware_test.go
@@ -1,204 +0,0 @@
-package middleware
-
-import (
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	"github.com/prysmaticlabs/prysm/v5/api"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-)
-
-func TestNormalizeQueryValuesHandler(t *testing.T) {
-	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, err := w.Write([]byte("next handler"))
-		require.NoError(t, err)
-	})
-
-	handler := NormalizeQueryValuesHandler(nextHandler)
-
-	tests := []struct {
-		name          string
-		inputQuery    string
-		expectedQuery string
-	}{
-		{
-			name:          "3 values",
-			inputQuery:    "key=value1,value2,value3",
-			expectedQuery: "key=value1&key=value2&key=value3", // replace with expected normalized value
-		},
-	}
-
-	for _, test := range tests {
-		t.Run(test.name, func(t *testing.T) {
-			req, err := http.NewRequest("GET", "/test?"+test.inputQuery, http.NoBody)
-			if err != nil {
-				t.Fatal(err)
-			}
-
-			rr := httptest.NewRecorder()
-			handler.ServeHTTP(rr, req)
-
-			if rr.Code != http.StatusOK {
-				t.Errorf("handler returned wrong status code: got %v want %v", rr.Code, http.StatusOK)
-			}
-
-			if req.URL.RawQuery != test.expectedQuery {
-				t.Errorf("query not normalized: got %v want %v", req.URL.RawQuery, test.expectedQuery)
-			}
-
-			if rr.Body.String() != "next handler" {
-				t.Errorf("next handler was not executed")
-			}
-		})
-	}
-}
-
-func TestContentTypeHandler(t *testing.T) {
-	acceptedMediaTypes := []string{api.JsonMediaType, api.OctetStreamMediaType}
-
-	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, err := w.Write([]byte("next handler"))
-		require.NoError(t, err)
-	})
-
-	handler := ContentTypeHandler(acceptedMediaTypes)(nextHandler)
-
-	tests := []struct {
-		name               string
-		contentType        string
-		expectedStatusCode int
-		isGet              bool
-	}{
-		{
-			name:               "Accepted Content-Type - application/json",
-			contentType:        api.JsonMediaType,
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "Accepted Content-Type - ssz format",
-			contentType:        api.OctetStreamMediaType,
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "Unsupported Content-Type - text/plain",
-			contentType:        "text/plain",
-			expectedStatusCode: http.StatusUnsupportedMediaType,
-		},
-		{
-			name:               "Missing Content-Type",
-			contentType:        "",
-			expectedStatusCode: http.StatusUnsupportedMediaType,
-		},
-		{
-			name:               "GET request skips content type check",
-			contentType:        "",
-			expectedStatusCode: http.StatusOK,
-			isGet:              true,
-		},
-		{
-			name:               "Content type contains charset is ok",
-			contentType:        "application/json; charset=utf-8",
-			expectedStatusCode: http.StatusOK,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			httpMethod := http.MethodPost
-			if tt.isGet {
-				httpMethod = http.MethodGet
-			}
-			req := httptest.NewRequest(httpMethod, "/", nil)
-			if tt.contentType != "" {
-				req.Header.Set("Content-Type", tt.contentType)
-			}
-			rr := httptest.NewRecorder()
-
-			handler.ServeHTTP(rr, req)
-
-			if status := rr.Code; status != tt.expectedStatusCode {
-				t.Errorf("handler returned wrong status code: got %v want %v", status, tt.expectedStatusCode)
-			}
-		})
-	}
-}
-
-func TestAcceptHeaderHandler(t *testing.T) {
-	acceptedTypes := []string{"application/json", "application/octet-stream"}
-
-	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		_, err := w.Write([]byte("next handler"))
-		require.NoError(t, err)
-	})
-
-	handler := AcceptHeaderHandler(acceptedTypes)(nextHandler)
-
-	tests := []struct {
-		name               string
-		acceptHeader       string
-		expectedStatusCode int
-	}{
-		{
-			name:               "Accepted Accept-Type - application/json",
-			acceptHeader:       "application/json",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "Accepted Accept-Type - application/octet-stream",
-			acceptHeader:       "application/octet-stream",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "Accepted Accept-Type with parameters",
-			acceptHeader:       "application/json;q=0.9, application/octet-stream;q=0.8",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "Unsupported Accept-Type - text/plain",
-			acceptHeader:       "text/plain",
-			expectedStatusCode: http.StatusNotAcceptable,
-		},
-		{
-			name:               "Missing Accept header",
-			acceptHeader:       "",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "*/* is accepted",
-			acceptHeader:       "*/*",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "application/* is accepted",
-			acceptHeader:       "application/*",
-			expectedStatusCode: http.StatusOK,
-		},
-		{
-			name:               "/* is unsupported",
-			acceptHeader:       "/*",
-			expectedStatusCode: http.StatusNotAcceptable,
-		},
-		{
-			name:               "application/ is unsupported",
-			acceptHeader:       "application/",
-			expectedStatusCode: http.StatusNotAcceptable,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			req := httptest.NewRequest("GET", "/", nil)
-			if tt.acceptHeader != "" {
-				req.Header.Set("Accept", tt.acceptHeader)
-			}
-			rr := httptest.NewRecorder()
-
-			handler.ServeHTTP(rr, req)
-
-			if status := rr.Code; status != tt.expectedStatusCode {
-				t.Errorf("handler returned wrong status code: got %v want %v", status, tt.expectedStatusCode)
-			}
-		})
-	}
-}
--- a/api/server/middleware_test.go
+++ b/api/server/middleware_test.go
@@ -0,0 +1,54 @@
+package server
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+)
+
+func TestNormalizeQueryValuesHandler(t *testing.T) {
+	nextHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := w.Write([]byte("next handler"))
+		require.NoError(t, err)
+	})
+
+	handler := NormalizeQueryValuesHandler(nextHandler)
+
+	tests := []struct {
+		name          string
+		inputQuery    string
+		expectedQuery string
+	}{
+		{
+			name:          "3 values",
+			inputQuery:    "key=value1,value2,value3",
+			expectedQuery: "key=value1&key=value2&key=value3", // replace with expected normalized value
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			req, err := http.NewRequest("GET", "/test?"+test.inputQuery, nil)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			rr := httptest.NewRecorder()
+			handler.ServeHTTP(rr, req)
+
+			if rr.Code != http.StatusOK {
+				t.Errorf("handler returned wrong status code: got %v want %v", rr.Code, http.StatusOK)
+			}
+
+			if req.URL.RawQuery != test.expectedQuery {
+				t.Errorf("query not normalized: got %v want %v", req.URL.RawQuery, test.expectedQuery)
+			}
+
+			if rr.Body.String() != "next handler" {
+				t.Errorf("next handler was not executed")
+			}
+		})
+	}
+}
--- a/api/server/structs/BUILD.bazel
+++ b/api/server/structs/BUILD.bazel
@@ -1,51 +0,0 @@
-load("@prysm//tools/go:def.bzl", "go_library", "go_test")
-
-go_library(
-    name = "go_default_library",
-    srcs = [
-        "block.go",
-        "conversions.go",
-        "conversions_block.go",
-        "conversions_state.go",
-        "endpoints_beacon.go",
-        "endpoints_blob.go",
-        "endpoints_builder.go",
-        "endpoints_config.go",
-        "endpoints_debug.go",
-        "endpoints_events.go",
-        "endpoints_lightclient.go",
-        "endpoints_node.go",
-        "endpoints_rewards.go",
-        "endpoints_validator.go",
-        "other.go",
-        "state.go",
-    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/api/server/structs",
-    visibility = ["//visibility:public"],
-    deps = [
-        "//api/server:go_default_library",
-        "//beacon-chain/state:go_default_library",
-        "//config/fieldparams:go_default_library",
-        "//consensus-types/interfaces:go_default_library",
-        "//consensus-types/primitives:go_default_library",
-        "//consensus-types/validator:go_default_library",
-        "//container/slice:go_default_library",
-        "//encoding/bytesutil:go_default_library",
-        "//math:go_default_library",
-        "//proto/engine/v1:go_default_library",
-        "//proto/prysm/v1alpha1:go_default_library",
-        "@com_github_ethereum_go_ethereum//common:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
-        "@com_github_pkg_errors//:go_default_library",
-    ],
-)
-
-go_test(
-    name = "go_default_test",
-    srcs = ["conversions_test.go"],
-    embed = [":go_default_library"],
-    deps = [
-        "//proto/prysm/v1alpha1:go_default_library",
-        "//testing/require:go_default_library",
-    ],
-)
--- a/api/server/structs/conversions_test.go
+++ b/api/server/structs/conversions_test.go
@@ -1,26 +0,0 @@
-package structs
-
-import (
-	"testing"
-
-	eth "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-)
-
-func TestDepositSnapshotFromConsensus(t *testing.T) {
-	ds := &eth.DepositSnapshot{
-		Finalized:      [][]byte{{0xde, 0xad, 0xbe, 0xef}, {0xca, 0xfe, 0xba, 0xbe}},
-		DepositRoot:    []byte{0xab, 0xcd},
-		DepositCount:   12345,
-		ExecutionHash:  []byte{0x12, 0x34},
-		ExecutionDepth: 67890,
-	}
-
-	res := DepositSnapshotFromConsensus(ds)
-	require.NotNil(t, res)
-	require.DeepEqual(t, []string{"0xdeadbeef", "0xcafebabe"}, res.Finalized)
-	require.Equal(t, "0xabcd", res.DepositRoot)
-	require.Equal(t, "12345", res.DepositCount)
-	require.Equal(t, "0x1234", res.ExecutionBlockHash)
-	require.Equal(t, "67890", res.ExecutionBlockHeight)
-}
--- a/api/server/structs/endpoints_blob.go
+++ b/api/server/structs/endpoints_blob.go
@@ -1,14 +0,0 @@
-package structs
-
-type SidecarsResponse struct {
-	Data []*Sidecar `json:"data"`
-}
-
-type Sidecar struct {
-	Index                    string                   `json:"index"`
-	Blob                     string                   `json:"blob"`
-	SignedBeaconBlockHeader  *SignedBeaconBlockHeader `json:"signed_block_header"`
-	KzgCommitment            string                   `json:"kzg_commitment"`
-	KzgProof                 string                   `json:"kzg_proof"`
-	CommitmentInclusionProof []string                 `json:"kzg_commitment_inclusion_proof"`
-}
--- a/api/server/structs/endpoints_lightclient.go
+++ b/api/server/structs/endpoints_lightclient.go
@@ -1,31 +0,0 @@
-package structs
-
-type LightClientBootstrapResponse struct {
-	Version string                `json:"version"`
-	Data    *LightClientBootstrap `json:"data"`
-}
-
-type LightClientBootstrap struct {
-	Header                     *BeaconBlockHeader `json:"header"`
-	CurrentSyncCommittee       *SyncCommittee     `json:"current_sync_committee"`
-	CurrentSyncCommitteeBranch []string           `json:"current_sync_committee_branch"`
-}
-
-type LightClientUpdate struct {
-	AttestedHeader          *BeaconBlockHeader `json:"attested_header"`
-	NextSyncCommittee       *SyncCommittee     `json:"next_sync_committee,omitempty"`
-	FinalizedHeader         *BeaconBlockHeader `json:"finalized_header,omitempty"`
-	SyncAggregate           *SyncAggregate     `json:"sync_aggregate"`
-	NextSyncCommitteeBranch []string           `json:"next_sync_committee_branch,omitempty"`
-	FinalityBranch          []string           `json:"finality_branch,omitempty"`
-	SignatureSlot           string             `json:"signature_slot"`
-}
-
-type LightClientUpdateWithVersion struct {
-	Version string             `json:"version"`
-	Data    *LightClientUpdate `json:"data"`
-}
-
-type LightClientUpdatesByRangeResponse struct {
-	Updates []*LightClientUpdateWithVersion `json:"updates"`
-}
--- a/api/server/middleware/util.go
+++ b/api/server/middleware/util.go
@@ -1,4 +1,4 @@
-package middleware
+package server

 import (
 	"net/url"
--- a/api/server/middleware/util_test.go
+++ b/api/server/middleware/util_test.go
@@ -1,10 +1,10 @@
-package middleware
+package server

 import (
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestNormalizeQueryValues(t *testing.T) {
--- a/async/BUILD.bazel
+++ b/async/BUILD.bazel
@@ -8,7 +8,7 @@ go_library(
        "multilock.go",
        "scatter.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/async",
+    importpath = "github.com/prysmaticlabs/prysm/v4/async",
    visibility = ["//visibility:public"],
    deps = ["@com_github_sirupsen_logrus//:go_default_library"],
 )
--- a/async/abool/BUILD.bazel
+++ b/async/abool/BUILD.bazel
@@ -3,7 +3,7 @@ load("@prysm//tools/go:def.bzl", "go_library", "go_test")
 go_library(
    name = "go_default_library",
    srcs = ["abool.go"],
-    importpath = "github.com/prysmaticlabs/prysm/v5/async/abool",
+    importpath = "github.com/prysmaticlabs/prysm/v4/async/abool",
    visibility = ["//visibility:public"],
 )

--- a/async/abool/abool_test.go
+++ b/async/abool/abool_test.go
@@ -88,7 +88,7 @@ func TestToggle(t *testing.T) {
 	}
 }

-func TestToggleMultipleTimes(t *testing.T) {
+func TestToogleMultipleTimes(t *testing.T) {
 	t.Parallel()

 	v := New()
@@ -101,16 +101,16 @@ func TestToggleMultipleTimes(t *testing.T) {

 		expected := i%2 != 0
 		if v.IsSet() != expected {
-			t.Fatalf("AtomicBool.Toggle() doesn't work after %d calls, expected: %v, got %v", i, expected, v.IsSet())
+			t.Fatalf("AtomicBool.Toogle() doesn't work after %d calls, expected: %v, got %v", i, expected, v.IsSet())
 		}

 		if pre == v.IsSet() {
-			t.Fatalf("AtomicBool.Toggle() returned wrong value at the %dth calls, expected: %v, got %v", i, !v.IsSet(), pre)
+			t.Fatalf("AtomicBool.Toogle() returned wrong value at the %dth calls, expected: %v, got %v", i, !v.IsSet(), pre)
 		}
 	}
 }

-func TestToggleAfterOverflow(t *testing.T) {
+func TestToogleAfterOverflow(t *testing.T) {
 	t.Parallel()

 	var value int32 = math.MaxInt32
@@ -122,7 +122,7 @@ func TestToggleAfterOverflow(t *testing.T) {
 	v.Toggle()
 	expected := math.MaxInt32%2 == 0
 	if v.IsSet() != expected {
-		t.Fatalf("AtomicBool.Toggle() doesn't work after overflow, expected: %v, got %v", expected, v.IsSet())
+		t.Fatalf("AtomicBool.Toogle() doesn't work after overflow, expected: %v, got %v", expected, v.IsSet())
 	}

 	// make sure overflow happened
@@ -135,7 +135,7 @@ func TestToggleAfterOverflow(t *testing.T) {
 	v.Toggle()
 	expected = !expected
 	if v.IsSet() != expected {
-		t.Fatalf("AtomicBool.Toggle() doesn't work after the second call after overflow, expected: %v, got %v", expected, v.IsSet())
+		t.Fatalf("AtomicBool.Toogle() doesn't work after the second call after overflow, expected: %v, got %v", expected, v.IsSet())
 	}
 }

--- a/async/benchmark_test.go
+++ b/async/benchmark_test.go
@@ -6,8 +6,8 @@ import (
 	"sync"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/async"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/async"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 	log "github.com/sirupsen/logrus"
 )

--- a/async/debounce_test.go
+++ b/async/debounce_test.go
@@ -7,10 +7,10 @@ import (
 	"testing"
 	"time"

-	"github.com/prysmaticlabs/prysm/v5/async"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/testing/util"
+	"github.com/prysmaticlabs/prysm/v4/async"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/util"
 )

 func TestDebounce_NoEvents(t *testing.T) {
--- a/async/event/BUILD.bazel
+++ b/async/event/BUILD.bazel
@@ -6,7 +6,7 @@ go_library(
        "feed.go",
        "subscription.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/async/event",
+    importpath = "github.com/prysmaticlabs/prysm/v4/async/event",
    visibility = ["//visibility:public"],
    deps = ["//time/mclock:go_default_library"],
 )
--- a/async/event/example_feed_test.go
+++ b/async/event/example_feed_test.go
@@ -19,7 +19,7 @@ package event_test
 import (
 	"fmt"

-	"github.com/prysmaticlabs/prysm/v5/async/event"
+	"github.com/prysmaticlabs/prysm/v4/async/event"
 )

 func ExampleFeed_acknowledgedEvents() {
--- a/async/event/example_scope_test.go
+++ b/async/event/example_scope_test.go
@@ -20,7 +20,7 @@ import (
 	"fmt"
 	"sync"

-	"github.com/prysmaticlabs/prysm/v5/async/event"
+	"github.com/prysmaticlabs/prysm/v4/async/event"
 )

 // This example demonstrates how SubscriptionScope can be used to control the lifetime of
--- a/async/event/example_subscription_test.go
+++ b/async/event/example_subscription_test.go
@@ -19,7 +19,7 @@ package event_test
 import (
 	"fmt"

-	"github.com/prysmaticlabs/prysm/v5/async/event"
+	"github.com/prysmaticlabs/prysm/v4/async/event"
 )

 func ExampleNewSubscription() {
--- a/async/event/feed.go
+++ b/async/event/feed.go
@@ -20,7 +20,6 @@ package event
 import (
 	"errors"
 	"reflect"
-	"slices"
 	"sync"
 )

@@ -220,9 +219,12 @@ type caseList []reflect.SelectCase

 // find returns the index of a case containing the given channel.
 func (cs caseList) find(channel interface{}) int {
-	return slices.IndexFunc(cs, func(selectCase reflect.SelectCase) bool {
-		return selectCase.Chan.Interface() == channel
-	})
+	for i, cas := range cs {
+		if cas.Chan.Interface() == channel {
+			return i
+		}
+	}
+	return -1
 }

 // delete removes the given case from cs.
--- a/async/event/feed_test.go
+++ b/async/event/feed_test.go
@@ -23,7 +23,7 @@ import (
 	"testing"
 	"time"

-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
 )

 func TestFeedPanics(t *testing.T) {
--- a/async/event/subscription.go
+++ b/async/event/subscription.go
@@ -21,7 +21,7 @@ import (
 	"sync"
 	"time"

-	"github.com/prysmaticlabs/prysm/v5/time/mclock"
+	"github.com/prysmaticlabs/prysm/v4/time/mclock"
 )

 // waitQuotient is divided against the max backoff time, in order to have N requests based on the full
--- a/async/event/subscription_test.go
+++ b/async/event/subscription_test.go
@@ -23,7 +23,7 @@ import (
 	"testing"
 	"time"

-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 var errInts = errors.New("error in subscribeInts")
--- a/async/every_test.go
+++ b/async/every_test.go
@@ -6,7 +6,7 @@ import (
 	"testing"
 	"time"

-	"github.com/prysmaticlabs/prysm/v5/async"
+	"github.com/prysmaticlabs/prysm/v4/async"
 )

 func TestEveryRuns(t *testing.T) {
--- a/async/scatter.go
+++ b/async/scatter.go
@@ -63,7 +63,7 @@ func Scatter(inputLen int, sFunc func(int, int, *sync.RWMutex) (interface{}, err
 	return results, nil
 }

-// calculateChunkSize calculates a suitable chunk size for the purposes of parallelization.
+// calculateChunkSize calculates a suitable chunk size for the purposes of parallelisation.
 func calculateChunkSize(items int) int {
 	// Start with a simple even split
 	chunkSize := items / runtime.GOMAXPROCS(0)
--- a/async/scatter_test.go
+++ b/async/scatter_test.go
@@ -5,9 +5,9 @@ import (
 	"sync"
 	"testing"

-	"github.com/prysmaticlabs/prysm/v5/async"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/async"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestDouble(t *testing.T) {
--- a/bazel.sh
+++ b/bazel.sh
@@ -2,7 +2,7 @@

 # This script serves as a wrapper around bazel to limit the scope of environment variables that
 # may change the action output. Using this script should result in a higher cache hit ratio for
-# cached actions with a more hermetic build.
+# cached actions with a more heremtic build.

 env -i \
 PATH=/usr/bin:/bin \
--- a/beacon-chain/blockchain/BUILD.bazel
+++ b/beacon-chain/blockchain/BUILD.bazel
@@ -6,7 +6,6 @@ go_library(
        "chain_info.go",
        "chain_info_forkchoice.go",
        "currently_syncing_block.go",
-        "defragment.go",
        "error.go",
        "execution_engine.go",
        "forkchoice_update_execution.go",
@@ -26,12 +25,11 @@ go_library(
        "receive_attestation.go",
        "receive_blob.go",
        "receive_block.go",
-        "receive_data_column.go",
        "service.go",
        "tracked_proposer.go",
        "weak_subjectivity_checks.go",
    ],
-    importpath = "github.com/prysmaticlabs/prysm/v5/beacon-chain/blockchain",
+    importpath = "github.com/prysmaticlabs/prysm/v4/beacon-chain/blockchain",
    visibility = [
        "//beacon-chain:__subpackages__",
        "//cmd/beacon-chain:__subpackages__",
@@ -49,11 +47,9 @@ go_library(
        "//beacon-chain/core/feed:go_default_library",
        "//beacon-chain/core/feed/state:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
-        "//beacon-chain/core/peerdas:go_default_library",
        "//beacon-chain/core/signing:go_default_library",
        "//beacon-chain/core/time:go_default_library",
        "//beacon-chain/core/transition:go_default_library",
-        "//beacon-chain/das:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/filesystem:go_default_library",
        "//beacon-chain/db/filters:go_default_library",
@@ -66,7 +62,6 @@ go_library(
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
-        "//beacon-chain/slasher/types:go_default_library",
        "//beacon-chain/startup:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//beacon-chain/state/stategen:go_default_library",
@@ -140,14 +135,12 @@ go_test(
        "//async/event:go_default_library",
        "//beacon-chain/blockchain/testing:go_default_library",
        "//beacon-chain/cache:go_default_library",
-        "//beacon-chain/cache/depositsnapshot:go_default_library",
-        "//beacon-chain/core/altair:go_default_library",
+        "//beacon-chain/cache/depositcache:go_default_library",
        "//beacon-chain/core/blocks:go_default_library",
        "//beacon-chain/core/feed/state:go_default_library",
        "//beacon-chain/core/helpers:go_default_library",
        "//beacon-chain/core/signing:go_default_library",
        "//beacon-chain/core/transition:go_default_library",
-        "//beacon-chain/das:go_default_library",
        "//beacon-chain/db:go_default_library",
        "//beacon-chain/db/filesystem:go_default_library",
        "//beacon-chain/db/testing:go_default_library",
@@ -161,7 +154,6 @@ go_test(
        "//beacon-chain/operations/slashings:go_default_library",
        "//beacon-chain/operations/voluntaryexits:go_default_library",
        "//beacon-chain/p2p:go_default_library",
-        "//beacon-chain/p2p/testing:go_default_library",
        "//beacon-chain/startup:go_default_library",
        "//beacon-chain/state:go_default_library",
        "//beacon-chain/state/state-native:go_default_library",
@@ -186,7 +178,6 @@ go_test(
        "//time:go_default_library",
        "//time/slots:go_default_library",
        "@com_github_ethereum_go_ethereum//common:go_default_library",
-        "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
        "@com_github_ethereum_go_ethereum//core/types:go_default_library",
        "@com_github_holiman_uint256//:go_default_library",
        "@com_github_pkg_errors//:go_default_library",
--- a/beacon-chain/blockchain/chain_info.go
+++ b/beacon-chain/blockchain/chain_info.go
@@ -6,18 +6,18 @@ import (
 	"time"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
-	f "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/forkchoice"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/forkchoice"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	"go.opencensus.io/trace"
 )

@@ -48,8 +48,6 @@ type ForkchoiceFetcher interface {
 	ForkChoiceDump(context.Context) (*forkchoice.Dump, error)
 	NewSlot(context.Context, primitives.Slot) error
 	ProposerBoost() [32]byte
-	RecentBlockSlot(root [32]byte) (primitives.Slot, error)
-	IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, error)
 }

 // TimeFetcher retrieves the Ethereum consensus data that's related to time.
@@ -336,21 +334,12 @@ func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index primiti
 	return v.PublicKey(), nil
 }

-// ForkChoicer returns the forkchoice interface.
-func (s *Service) ForkChoicer() f.ForkChoicer {
-	return s.cfg.ForkChoiceStore
-}
-
 // IsOptimistic returns true if the current head is optimistic.
 func (s *Service) IsOptimistic(_ context.Context) (bool, error) {
 	if slots.ToEpoch(s.CurrentSlot()) < params.BeaconConfig().BellatrixForkEpoch {
 		return false, nil
 	}
 	s.headLock.RLock()
-	if s.head == nil {
-		s.headLock.RUnlock()
-		return false, ErrNilHead
-	}
 	headRoot := s.head.root
 	headSlot := s.head.slot
 	headOptimistic := s.head.optimistic
@@ -399,6 +388,14 @@ func (s *Service) InForkchoice(root [32]byte) bool {
 	return s.cfg.ForkChoiceStore.HasNode(root)
 }

+// IsViableForCheckpoint returns whether the given checkpoint is a checkpoint in any
+// chain known to forkchoice
+func (s *Service) IsViableForCheckpoint(cp *forkchoicetypes.Checkpoint) (bool, error) {
+	s.cfg.ForkChoiceStore.RLock()
+	defer s.cfg.ForkChoiceStore.RUnlock()
+	return s.cfg.ForkChoiceStore.IsViableForCheckpoint(cp)
+}
+
 // IsOptimisticForRoot takes the root as argument instead of the current head
 // and returns true if it is optimistic.
 func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error) {
@@ -510,6 +507,13 @@ func (s *Service) Ancestor(ctx context.Context, root []byte, slot primitives.Slo
 	return ar[:], nil
 }

+// SetOptimisticToInvalid wraps the corresponding method in forkchoice
+func (s *Service) SetOptimisticToInvalid(ctx context.Context, root, parent, lvh [32]byte) ([][32]byte, error) {
+	s.cfg.ForkChoiceStore.Lock()
+	defer s.cfg.ForkChoiceStore.Unlock()
+	return s.cfg.ForkChoiceStore.SetOptimisticToInvalid(ctx, root, parent, lvh)
+}
+
 // SetGenesisTime sets the genesis time of beacon chain.
 func (s *Service) SetGenesisTime(t time.Time) {
 	s.genesisTime = t
@@ -541,16 +545,3 @@ func (s *Service) RecentBlockSlot(root [32]byte) (primitives.Slot, error) {
 	defer s.cfg.ForkChoiceStore.RUnlock()
 	return s.cfg.ForkChoiceStore.Slot(root)
 }
-
-// inRegularSync queries the initial sync service to
-// determine if the node is in regular sync or is still
-// syncing to the head of the chain.
-func (s *Service) inRegularSync() bool {
-	return s.cfg.SyncChecker.Synced()
-}
-
-// validating returns true if the beacon is tracking some validators that have
-// registered for proposing.
-func (s *Service) validating() bool {
-	return s.cfg.TrackedValidatorsCache.Validating()
-}
--- a/beacon-chain/blockchain/chain_info_forkchoice.go
+++ b/beacon-chain/blockchain/chain_info_forkchoice.go
@@ -3,9 +3,9 @@ package blockchain
 import (
 	"context"

-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/forkchoice"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/forkchoice"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
 )

 // CachedHeadRoot returns the corresponding value from Forkchoice
--- a/beacon-chain/blockchain/chain_info_norace_test.go
+++ b/beacon-chain/blockchain/chain_info_norace_test.go
@@ -4,14 +4,14 @@ import (
 	"context"
 	"testing"

-	testDB "github.com/prysmaticlabs/prysm/v5/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/testing/util"
+	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state/stategen"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/util"
 )

 func TestHeadSlot_DataRace(t *testing.T) {
--- a/beacon-chain/blockchain/chain_info_test.go
+++ b/beacon-chain/blockchain/chain_info_test.go
@@ -5,21 +5,21 @@ import (
 	"testing"
 	"time"

-	testDB "github.com/prysmaticlabs/prysm/v5/beacon-chain/db/testing"
-	doublylinkedtree "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/doubly-linked-tree"
-	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	state_native "github.com/prysmaticlabs/prysm/v5/beacon-chain/state/state-native"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/testing/util"
+	testDB "github.com/prysmaticlabs/prysm/v4/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/doubly-linked-tree"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	enginev1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/util"
 	"google.golang.org/protobuf/proto"
 )

@@ -429,11 +429,6 @@ func TestService_IsOptimistic(t *testing.T) {
 	opt, err = c.IsOptimistic(ctx)
 	require.NoError(t, err)
 	require.Equal(t, true, opt)
-
-	// If head is nil, for some reason, an error should be returned rather than panic.
-	c = &Service{}
-	_, err = c.IsOptimistic(ctx)
-	require.ErrorIs(t, err, ErrNilHead)
 }

 func TestService_IsOptimisticBeforeBellatrix(t *testing.T) {
--- a/beacon-chain/blockchain/defragment.go
+++ b/beacon-chain/blockchain/defragment.go
@@ -1,27 +0,0 @@
-package blockchain
-
-import (
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/config/features"
-	"github.com/prysmaticlabs/prysm/v5/time"
-)
-
-var stateDefragmentationTime = promauto.NewSummary(prometheus.SummaryOpts{
-	Name: "head_state_defragmentation_milliseconds",
-	Help: "Milliseconds it takes to defragment the head state",
-})
-
-// This method defragments our state, so that any specific fields which have
-// a higher number of fragmented indexes are reallocated to a new separate slice for
-// that field.
-func (s *Service) defragmentState(st state.BeaconState) {
-	if !features.Get().EnableExperimentalState {
-		return
-	}
-	startTime := time.Now()
-	st.Defragment()
-	elapsedTime := time.Since(startTime)
-	stateDefragmentationTime.Observe(float64(elapsedTime.Milliseconds()))
-}
--- a/beacon-chain/blockchain/error.go
+++ b/beacon-chain/blockchain/error.go
@@ -28,12 +28,9 @@ var (
 	// ErrNotCheckpoint is returned when a given checkpoint is not a
 	// checkpoint in any chain known to forkchoice
 	ErrNotCheckpoint = errors.New("not a checkpoint in forkchoice")
-	// ErrNilHead is returned when no head is present in the blockchain service.
-	ErrNilHead = errors.New("nil head")
 )

 var errMaxBlobsExceeded = errors.New("Expected commitments in block exceeds MAX_BLOBS_PER_BLOCK")
-var errMaxDataColumnsExceeded = errors.New("Expected data columns for node exceeds NUMBER_OF_COLUMNS")

 // An invalid block is the block that fails state transition based on the core protocol rules.
 // The beacon node shall not be accepting nor building blocks that branch off from an invalid block.
--- a/beacon-chain/blockchain/error_test.go
+++ b/beacon-chain/blockchain/error_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"

 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
 )

 func TestIsInvalidBlock(t *testing.T) {
--- a/beacon-chain/blockchain/execution_engine.go
+++ b/beacon-chain/blockchain/execution_engine.go
@@ -7,23 +7,22 @@ import (

 	"github.com/ethereum/go-ethereum/common"
 	"github.com/pkg/errors"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/helpers"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/time"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/transition"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/execution"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	"github.com/prysmaticlabs/prysm/v5/config/features"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	payloadattribute "github.com/prysmaticlabs/prysm/v5/consensus-types/payload-attribute"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	enginev1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	"github.com/prysmaticlabs/prysm/v5/runtime/version"
-	"github.com/prysmaticlabs/prysm/v5/time/slots"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/time"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/transition"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/execution"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	consensusblocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	payloadattribute "github.com/prysmaticlabs/prysm/v4/consensus-types/payload-attribute"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	enginev1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	"github.com/prysmaticlabs/prysm/v4/runtime/version"
+	"github.com/prysmaticlabs/prysm/v4/time/slots"
 	"github.com/sirupsen/logrus"
 	"go.opencensus.io/trace"
 )
@@ -32,18 +31,21 @@ const blobCommitmentVersionKZG uint8 = 0x01

 var defaultLatestValidHash = bytesutil.PadTo([]byte{0xff}, 32)

+// notifyForkchoiceUpdateArg is the argument for the forkchoice update notification `notifyForkchoiceUpdate`.
+type notifyForkchoiceUpdateArg struct {
+	headState state.BeaconState
+	headRoot  [32]byte
+	headBlock interfaces.ReadOnlyBeaconBlock
+}
+
 // notifyForkchoiceUpdate signals execution engine the fork choice updates. Execution engine should:
 // 1. Re-organizes the execution payload chain and corresponding state to make head_block_hash the head.
 // 2. Applies finality to the execution state: it irreversibly persists the chain of all execution payloads and corresponding state, up to and including finalized_block_hash.
-func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*enginev1.PayloadIDBytes, error) {
+func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *notifyForkchoiceUpdateArg) (*enginev1.PayloadIDBytes, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.notifyForkchoiceUpdate")
 	defer span.End()

-	if arg.headBlock.IsNil() {
-		log.Error("Head block is nil")
-		return nil, nil
-	}
-	headBlk := arg.headBlock.Block()
+	headBlk := arg.headBlock
 	if headBlk == nil || headBlk.IsNil() || headBlk.Body().IsNil() {
 		log.Error("Head block is nil")
 		return nil, nil
@@ -69,13 +71,14 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 		SafeBlockHash:      justifiedHash[:],
 		FinalizedBlockHash: finalizedHash[:],
 	}
-	if arg.attributes == nil {
-		arg.attributes = payloadattribute.EmptyWithVersion(headBlk.Version())
-	}
-	payloadID, lastValidHash, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, arg.attributes)
+
+	nextSlot := s.CurrentSlot() + 1 // Cache payload ID for next slot proposer.
+	hasAttr, attr := s.getPayloadAttribute(ctx, arg.headState, nextSlot, arg.headRoot[:])
+
+	payloadID, lastValidHash, err := s.cfg.ExecutionEngineCaller.ForkchoiceUpdated(ctx, fcs, attr)
 	if err != nil {
-		switch {
-		case errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus):
+		switch err {
+		case execution.ErrAcceptedSyncingPayloadStatus:
 			forkchoiceUpdatedOptimisticNodeCount.Inc()
 			log.WithFields(logrus.Fields{
 				"headSlot":                  headBlk.Slot(),
@@ -83,7 +86,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 				"finalizedPayloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(finalizedHash[:])),
 			}).Info("Called fork choice updated with optimistic block")
 			return payloadID, nil
-		case errors.Is(err, execution.ErrInvalidPayloadStatus):
+		case execution.ErrInvalidPayloadStatus:
 			forkchoiceUpdatedInvalidNodeCount.Inc()
 			headRoot := arg.headRoot
 			if len(lastValidHash) == 0 {
@@ -118,11 +121,10 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 				log.WithError(err).Error("Could not get head state")
 				return nil, nil
 			}
-			pid, err := s.notifyForkchoiceUpdate(ctx, &fcuConfig{
-				headState:  st,
-				headRoot:   r,
-				headBlock:  b,
-				attributes: arg.attributes,
+			pid, err := s.notifyForkchoiceUpdate(ctx, &notifyForkchoiceUpdateArg{
+				headState: st,
+				headRoot:  r,
+				headBlock: b.Block(),
 			})
 			if err != nil {
 				return nil, err // Returning err because it's recursive here.
@@ -139,6 +141,7 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 				"newHeadRoot":          fmt.Sprintf("%#x", bytesutil.Trunc(r[:])),
 			}).Warn("Pruned invalid blocks")
 			return pid, invalidBlock{error: ErrInvalidPayload, root: arg.headRoot, invalidAncestorRoots: invalidRoots}
+
 		default:
 			log.WithError(err).Error(ErrUndefinedExecutionEngineError)
 			return nil, nil
@@ -150,8 +153,6 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, arg *fcuConfig) (*
 		return nil, nil
 	}
 	// If the forkchoice update call has an attribute, update the payload ID cache.
-	hasAttr := arg.attributes != nil && !arg.attributes.IsEmpty()
-	nextSlot := s.CurrentSlot() + 1
 	if hasAttr && payloadID != nil {
 		var pId [8]byte
 		copy(pId[:], payloadID[:])
@@ -230,18 +231,18 @@ func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
 	} else {
 		lastValidHash, err = s.cfg.ExecutionEngineCaller.NewPayload(ctx, payload, []common.Hash{}, &common.Hash{} /*empty version hashes and root before Deneb*/)
 	}
-	switch {
-	case err == nil:
+	switch err {
+	case nil:
 		newPayloadValidNodeCount.Inc()
 		return true, nil
-	case errors.Is(err, execution.ErrAcceptedSyncingPayloadStatus):
+	case execution.ErrAcceptedSyncingPayloadStatus:
 		newPayloadOptimisticNodeCount.Inc()
 		log.WithFields(logrus.Fields{
 			"slot":             blk.Block().Slot(),
 			"payloadBlockHash": fmt.Sprintf("%#x", bytesutil.Trunc(payload.BlockHash())),
 		}).Info("Called new payload with optimistic block")
 		return false, nil
-	case errors.Is(err, execution.ErrInvalidPayloadStatus):
+	case execution.ErrInvalidPayloadStatus:
 		lvh := bytesutil.ToBytes32(lastValidHash)
 		return false, invalidBlock{
 			error:         ErrInvalidPayload,
@@ -255,7 +256,7 @@ func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int,
 // reportInvalidBlock deals with the event that an invalid block was detected by the execution layer
 func (s *Service) pruneInvalidBlock(ctx context.Context, root, parentRoot, lvh [32]byte) error {
 	newPayloadInvalidNodeCount.Inc()
-	invalidRoots, err := s.cfg.ForkChoiceStore.SetOptimisticToInvalid(ctx, root, parentRoot, lvh)
+	invalidRoots, err := s.SetOptimisticToInvalid(ctx, root, parentRoot, lvh)
 	if err != nil {
 		return err
 	}
@@ -275,59 +276,44 @@ func (s *Service) pruneInvalidBlock(ctx context.Context, root, parentRoot, lvh [

 // getPayloadAttributes returns the payload attributes for the given state and slot.
 // The attribute is required to initiate a payload build process in the context of an `engine_forkchoiceUpdated` call.
-func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState, slot primitives.Slot, headRoot []byte) payloadattribute.Attributer {
+func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState, slot primitives.Slot, headRoot []byte) (bool, payloadattribute.Attributer) {
 	emptyAttri := payloadattribute.EmptyWithVersion(st.Version())

-	// If it is an epoch boundary then process slots to get the right
-	// shuffling before checking if the proposer is tracked. Otherwise
-	// perform this check before. This is cheap as the NSC has already been updated.
-	var val cache.TrackedValidator
-	var ok bool
-	e := slots.ToEpoch(slot)
-	stateEpoch := slots.ToEpoch(st.Slot())
-	if e == stateEpoch {
-		val, ok = s.trackedProposer(st, slot)
-		if !ok {
-			return emptyAttri
-		}
+	val, ok := s.trackedProposer(st, slot)
+	if !ok && !features.Get().PrepareAllPayloads {
+		return false, emptyAttri
 	}
+
+	// Get previous randao.
 	st = st.Copy()
 	if slot > st.Slot() {
 		var err error
 		st, err = transition.ProcessSlotsUsingNextSlotCache(ctx, st, headRoot, slot)
 		if err != nil {
 			log.WithError(err).Error("Could not process slots to get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 	}
-	if e > stateEpoch {
-		emptyAttri := payloadattribute.EmptyWithVersion(st.Version())
-		val, ok = s.trackedProposer(st, slot)
-		if !ok {
-			return emptyAttri
-		}
-	}
-	// Get previous randao.
 	prevRando, err := helpers.RandaoMix(st, time.CurrentEpoch(st))
 	if err != nil {
 		log.WithError(err).Error("Could not get randao mix to get payload attribute")
-		return emptyAttri
+		return false, emptyAttri
 	}

 	// Get timestamp.
 	t, err := slots.ToTime(uint64(s.genesisTime.Unix()), slot)
 	if err != nil {
 		log.WithError(err).Error("Could not get timestamp to get payload attribute")
-		return emptyAttri
+		return false, emptyAttri
 	}

 	var attr payloadattribute.Attributer
 	switch st.Version() {
-	case version.Deneb, version.Electra:
-		withdrawals, _, err := st.ExpectedWithdrawals()
+	case version.Deneb:
+		withdrawals, err := st.ExpectedWithdrawals()
 		if err != nil {
 			log.WithError(err).Error("Could not get expected withdrawals to get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 		attr, err = payloadattribute.New(&enginev1.PayloadAttributesV3{
 			Timestamp:             uint64(t.Unix()),
@@ -338,13 +324,13 @@ func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState,
 		})
 		if err != nil {
 			log.WithError(err).Error("Could not get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 	case version.Capella:
-		withdrawals, _, err := st.ExpectedWithdrawals()
+		withdrawals, err := st.ExpectedWithdrawals()
 		if err != nil {
 			log.WithError(err).Error("Could not get expected withdrawals to get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 		attr, err = payloadattribute.New(&enginev1.PayloadAttributesV2{
 			Timestamp:             uint64(t.Unix()),
@@ -354,7 +340,7 @@ func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState,
 		})
 		if err != nil {
 			log.WithError(err).Error("Could not get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 	case version.Bellatrix:
 		attr, err = payloadattribute.New(&enginev1.PayloadAttributes{
@@ -364,14 +350,14 @@ func (s *Service) getPayloadAttribute(ctx context.Context, st state.BeaconState,
 		})
 		if err != nil {
 			log.WithError(err).Error("Could not get payload attribute")
-			return emptyAttri
+			return false, emptyAttri
 		}
 	default:
 		log.WithField("version", st.Version()).Error("Could not get payload attribute due to unknown state version")
-		return emptyAttri
+		return false, emptyAttri
 	}

-	return attr
+	return true, attr
 }

 // removeInvalidBlockAndState removes the invalid block, blob and its corresponding state from the cache and DB.
@@ -386,9 +372,9 @@ func (s *Service) removeInvalidBlockAndState(ctx context.Context, blkRoots [][32
 			// This is an irreparable condition, it would me a justified or finalized block has become invalid.
 			return err
 		}
-		if err := s.blobStorage.Remove(root); err != nil {
-			// Blobs may not exist for some blocks, leading to deletion failures. Log such errors at debug level.
-			log.WithError(err).Debug("Could not remove blob from blob storage")
+		// No op if the sidecar does not exist.
+		if err := s.cfg.BeaconDB.DeleteBlobSidecars(ctx, root); err != nil {
+			return err
 		}
 	}
 	return nil
--- a/beacon-chain/blockchain/execution_engine_test.go
+++ b/beacon-chain/blockchain/execution_engine_test.go
@@ -7,25 +7,25 @@ import (

 	"github.com/ethereum/go-ethereum/common"
 	gethtypes "github.com/ethereum/go-ethereum/core/types"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/cache"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/core/blocks"
-	"github.com/prysmaticlabs/prysm/v5/beacon-chain/execution"
-	mockExecution "github.com/prysmaticlabs/prysm/v5/beacon-chain/execution/testing"
-	forkchoicetypes "github.com/prysmaticlabs/prysm/v5/beacon-chain/forkchoice/types"
-	bstate "github.com/prysmaticlabs/prysm/v5/beacon-chain/state"
-	state_native "github.com/prysmaticlabs/prysm/v5/beacon-chain/state/state-native"
-	"github.com/prysmaticlabs/prysm/v5/config/features"
-	fieldparams "github.com/prysmaticlabs/prysm/v5/config/fieldparams"
-	"github.com/prysmaticlabs/prysm/v5/config/params"
-	consensusblocks "github.com/prysmaticlabs/prysm/v5/consensus-types/blocks"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/interfaces"
-	"github.com/prysmaticlabs/prysm/v5/consensus-types/primitives"
-	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
-	v1 "github.com/prysmaticlabs/prysm/v5/proto/engine/v1"
-	ethpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1"
-	"github.com/prysmaticlabs/prysm/v5/testing/assert"
-	"github.com/prysmaticlabs/prysm/v5/testing/require"
-	"github.com/prysmaticlabs/prysm/v5/testing/util"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/cache"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/core/blocks"
+	"github.com/prysmaticlabs/prysm/v4/beacon-chain/execution"
+	mockExecution "github.com/prysmaticlabs/prysm/v4/beacon-chain/execution/testing"
+	forkchoicetypes "github.com/prysmaticlabs/prysm/v4/beacon-chain/forkchoice/types"
+	bstate "github.com/prysmaticlabs/prysm/v4/beacon-chain/state"
+	state_native "github.com/prysmaticlabs/prysm/v4/beacon-chain/state/state-native"
+	"github.com/prysmaticlabs/prysm/v4/config/features"
+	fieldparams "github.com/prysmaticlabs/prysm/v4/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/v4/config/params"
+	consensusblocks "github.com/prysmaticlabs/prysm/v4/consensus-types/blocks"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/interfaces"
+	"github.com/prysmaticlabs/prysm/v4/consensus-types/primitives"
+	"github.com/prysmaticlabs/prysm/v4/encoding/bytesutil"
+	v1 "github.com/prysmaticlabs/prysm/v4/proto/engine/v1"
+	ethpb "github.com/prysmaticlabs/prysm/v4/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/v4/testing/assert"
+	"github.com/prysmaticlabs/prysm/v4/testing/require"
+	"github.com/prysmaticlabs/prysm/v4/testing/util"
 )

 func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
@@ -56,14 +56,11 @@ func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, fcs.InsertNode(ctx, state, blkRoot))

-	sb := &ethpb.SignedBeaconBlockBellatrix{
-		Block: &ethpb.BeaconBlockBellatrix{
-			Body: &ethpb.BeaconBlockBodyBellatrix{
-				ExecutionPayload: &v1.ExecutionPayload{},
-			},
+	b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
+		Body: &ethpb.BeaconBlockBodyBellatrix{
+			ExecutionPayload: &v1.ExecutionPayload{},
 		},
-	}
-	b, err := consensusblocks.NewSignedBeaconBlock(sb)
+	})
 	require.NoError(t, err)

 	pid := &v1.PayloadIDBytes{1}
@@ -75,7 +72,7 @@ func Test_NotifyForkchoiceUpdate_GetPayloadAttrErrorCanContinue(t *testing.T) {
 	// Intentionally generate a bad state such that `hash_tree_root` fails during `process_slot`
 	s, err := state_native.InitializeFromProtoPhase0(&ethpb.BeaconState{})
 	require.NoError(t, err)
-	arg := &fcuConfig{
+	arg := &notifyForkchoiceUpdateArg{
 		headState: s,
 		headRoot:  [32]byte{},
 		headBlock: b,
@@ -116,7 +113,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {

 	tests := []struct {
 		name             string
-		blk              interfaces.ReadOnlySignedBeaconBlock
+		blk              interfaces.ReadOnlyBeaconBlock
 		headRoot         [32]byte
 		finalizedRoot    [32]byte
 		justifiedRoot    [32]byte
@@ -125,24 +122,24 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	}{
 		{
 			name: "phase0 block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}})
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}})
 				require.NoError(t, err)
 				return b
 			}(),
 		},
 		{
 			name: "altair block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockAltair{Block: &ethpb.BeaconBlockAltair{Body: &ethpb.BeaconBlockBodyAltair{}}})
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockAltair{Body: &ethpb.BeaconBlockBodyAltair{}})
 				require.NoError(t, err)
 				return b
 			}(),
 		},
 		{
 			name: "not execution block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{
 							ParentHash:    make([]byte, fieldparams.RootLength),
@@ -151,25 +148,23 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 							ReceiptsRoot:  make([]byte, fieldparams.RootLength),
 							LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
 							PrevRandao:    make([]byte, fieldparams.RootLength),
-							ExtraData:     make([]byte, 0),
 							BaseFeePerGas: make([]byte, fieldparams.RootLength),
 							BlockHash:     make([]byte, fieldparams.RootLength),
-							Transactions:  make([][]byte, 0),
 						},
 					},
-				}})
+				})
 				require.NoError(t, err)
 				return b
 			}(),
 		},
 		{
 			name: "happy case: finalized root is altair block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
 					},
-				}})
+				})
 				require.NoError(t, err)
 				return b
 			}(),
@@ -178,12 +173,12 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "happy case: finalized root is bellatrix block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
 					},
-				}})
+				})
 				require.NoError(t, err)
 				return b
 			}(),
@@ -192,12 +187,12 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "forkchoice updated with optimistic block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
 					},
-				}})
+				})
 				require.NoError(t, err)
 				return b
 			}(),
@@ -207,12 +202,12 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		},
 		{
 			name: "forkchoice updated with invalid block",
-			blk: func() interfaces.ReadOnlySignedBeaconBlock {
-				b, err := consensusblocks.NewSignedBeaconBlock(&ethpb.SignedBeaconBlockBellatrix{Block: &ethpb.BeaconBlockBellatrix{
+			blk: func() interfaces.ReadOnlyBeaconBlock {
+				b, err := consensusblocks.NewBeaconBlock(&ethpb.BeaconBlockBellatrix{
 					Body: &ethpb.BeaconBlockBodyBellatrix{
 						ExecutionPayload: &v1.ExecutionPayload{},
 					},
-				}})
+				})
 				require.NoError(t, err)
 				return b
 			}(),
@@ -230,7 +225,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 			st, _ := util.DeterministicGenesisState(t, 1)
 			require.NoError(t, beaconDB.SaveState(ctx, st, tt.finalizedRoot))
 			require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, tt.finalizedRoot))
-			arg := &fcuConfig{
+			arg := &notifyForkchoiceUpdateArg{
 				headState: st,
 				headRoot:  tt.headRoot,
 				headBlock: tt.blk,
@@ -310,9 +305,9 @@ func Test_NotifyForkchoiceUpdate_NIlLVH(t *testing.T) {

 	require.NoError(t, beaconDB.SaveState(ctx, st, bra))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bra))
-	a := &fcuConfig{
+	a := &notifyForkchoiceUpdateArg{
 		headState: st,
-		headBlock: wbd,
+		headBlock: wbd.Block(),
 		headRoot:  brd,
 	}
 	_, err = service.notifyForkchoiceUpdate(ctx, a)
@@ -447,9 +442,9 @@ func Test_NotifyForkchoiceUpdateRecursive_DoublyLinkedTree(t *testing.T) {

 	require.NoError(t, beaconDB.SaveState(ctx, st, bra))
 	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, bra))
-	a := &fcuConfig{
+	a := &notifyForkchoiceUpdateArg{
 		headState: st,
-		headBlock: wbg,
+		headBlock: wbg.Block(),
 		headRoot:  brg,
 	}
 	_, err = service.notifyForkchoiceUpdate(ctx, a)
@@ -496,10 +491,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 					ReceiptsRoot:  make([]byte, fieldparams.RootLength),
 					LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
 					PrevRandao:    make([]byte, fieldparams.RootLength),
-					ExtraData:     make([]byte, 0),
 					BaseFeePerGas: make([]byte, fieldparams.RootLength),
 					BlockHash:     make([]byte, fieldparams.RootLength),
-					Transactions:  make([][]byte, 0),
 				},
 			},
 		},
@@ -601,10 +594,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 								ReceiptsRoot:  make([]byte, fieldparams.RootLength),
 								LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
 								PrevRandao:    make([]byte, fieldparams.RootLength),
-								ExtraData:     make([]byte, 0),
 								BaseFeePerGas: make([]byte, fieldparams.RootLength),
 								BlockHash:     make([]byte, fieldparams.RootLength),
-								Transactions:  make([][]byte, 0),
 							},
 						},
 					},
@@ -789,23 +780,23 @@ func Test_GetPayloadAttribute(t *testing.T) {
 	ctx := tr.ctx

 	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
-	attr := service.getPayloadAttribute(ctx, st, 0, []byte{})
-	require.Equal(t, true, attr.IsEmpty())
+	hasPayload, _ := service.getPayloadAttribute(ctx, st, 0, []byte{})
+	require.Equal(t, false, hasPayload)

 	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, Index: 0})
 	// Cache hit, advance state, no fee recipient
 	slot := primitives.Slot(1)
 	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
-	require.Equal(t, false, attr.IsEmpty())
+	hasPayload, attr := service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
 	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())

 	// Cache hit, advance state, has fee recipient
 	suggestedAddr := common.HexToAddress("123")
 	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, FeeRecipient: primitives.ExecutionAddress(suggestedAddr), Index: 0})
 	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
-	require.Equal(t, false, attr.IsEmpty())
+	hasPayload, attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
 }

@@ -819,8 +810,8 @@ func Test_GetPayloadAttribute_PrepareAllPayloads(t *testing.T) {
 	ctx := tr.ctx

 	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
-	attr := service.getPayloadAttribute(ctx, st, 0, []byte{})
-	require.Equal(t, false, attr.IsEmpty())
+	hasPayload, attr := service.getPayloadAttribute(ctx, st, 0, []byte{})
+	require.Equal(t, true, hasPayload)
 	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
 }

@@ -829,15 +820,15 @@ func Test_GetPayloadAttributeV2(t *testing.T) {
 	ctx := tr.ctx

 	st, _ := util.DeterministicGenesisStateCapella(t, 1)
-	attr := service.getPayloadAttribute(ctx, st, 0, []byte{})
-	require.Equal(t, true, attr.IsEmpty())
+	hasPayload, _ := service.getPayloadAttribute(ctx, st, 0, []byte{})
+	require.Equal(t, false, hasPayload)

 	// Cache hit, advance state, no fee recipient
 	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, Index: 0})
 	slot := primitives.Slot(1)
 	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
-	require.Equal(t, false, attr.IsEmpty())
+	hasPayload, attr := service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
 	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
 	a, err := attr.Withdrawals()
 	require.NoError(t, err)
@@ -847,71 +838,49 @@ func Test_GetPayloadAttributeV2(t *testing.T) {
 	suggestedAddr := common.HexToAddress("123")
 	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, FeeRecipient: primitives.ExecutionAddress(suggestedAddr), Index: 0})
 	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
-	require.Equal(t, false, attr.IsEmpty())
+	hasPayload, attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
 	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
 	a, err = attr.Withdrawals()
 	require.NoError(t, err)
 	require.Equal(t, 0, len(a))
 }

-func Test_GetPayloadAttributeV3(t *testing.T) {
-	var testCases = []struct {
-		name string
-		st   bstate.BeaconState
-	}{
-		{
-			name: "deneb",
-			st: func() bstate.BeaconState {
-				st, _ := util.DeterministicGenesisStateDeneb(t, 1)
-				return st
-			}(),
-		},
-		{
-			name: "electra",
-			st: func() bstate.BeaconState {
-				st, _ := util.DeterministicGenesisStateElectra(t, 1)
-				return st
-			}(),
-		},
-	}
+func Test_GetPayloadAttributeDeneb(t *testing.T) {
+	service, tr := minimalTestService(t, WithPayloadIDCache(cache.NewPayloadIDCache()))
+	ctx := tr.ctx

-	for _, test := range testCases {
-		t.Run(test.name, func(t *testing.T) {
-			service, tr := minimalTestService(t, WithPayloadIDCache(cache.NewPayloadIDCache()))
-			ctx := tr.ctx
+	st, _ := util.DeterministicGenesisStateDeneb(t, 1)
+	hasPayload, _ := service.getPayloadAttribute(ctx, st, 0, []byte{})
+	require.Equal(t, false, hasPayload)

-			attr := service.getPayloadAttribute(ctx, test.st, 0, []byte{})
-			require.Equal(t, true, attr.IsEmpty())
+	// Cache hit, advance state, no fee recipient
+	slot := primitives.Slot(1)
+	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, Index: 0})
+	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
+	hasPayload, attr := service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
+	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
+	a, err := attr.Withdrawals()
+	require.NoError(t, err)
+	require.Equal(t, 0, len(a))

-			// Cache hit, advance state, no fee recipient
-			slot := primitives.Slot(1)
-			service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, Index: 0})
-			service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-			attr = service.getPayloadAttribute(ctx, test.st, slot, params.BeaconConfig().ZeroHash[:])
-			require.Equal(t, false, attr.IsEmpty())
-			require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(attr.SuggestedFeeRecipient()).String())
-			a, err := attr.Withdrawals()
-			require.NoError(t, err)
-			require.Equal(t, 0, len(a))
+	// Cache hit, advance state, has fee recipient
+	suggestedAddr := common.HexToAddress("123")
+	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, FeeRecipient: primitives.ExecutionAddress(suggestedAddr), Index: 0})
+	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
+	hasPayload, attr = service.getPayloadAttribute(ctx, st, slot, params.BeaconConfig().ZeroHash[:])
+	require.Equal(t, true, hasPayload)
+	require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
+	a, err = attr.Withdrawals()
+	require.NoError(t, err)
+	require.Equal(t, 0, len(a))

-			// Cache hit, advance state, has fee recipient
-			suggestedAddr := common.HexToAddress("123")
-			service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, FeeRecipient: primitives.ExecutionAddress(suggestedAddr), Index: 0})
-			service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-			attr = service.getPayloadAttribute(ctx, test.st, slot, params.BeaconConfig().ZeroHash[:])
-			require.Equal(t, false, attr.IsEmpty())
-			require.Equal(t, suggestedAddr, common.BytesToAddress(attr.SuggestedFeeRecipient()))
-			a, err = attr.Withdrawals()
-			require.NoError(t, err)
-			require.Equal(t, 0, len(a))
+	attrV3, err := attr.PbV3()
+	require.NoError(t, err)
+	hr := service.headRoot()
+	require.Equal(t, hr, [32]byte(attrV3.ParentBeaconBlockRoot))

-			attrV3, err := attr.PbV3()
-			require.NoError(t, err)
-			hr := service.headRoot()
-			require.Equal(t, hr, [32]byte(attrV3.ParentBeaconBlockRoot))
-		})
-	}
 }

 func Test_UpdateLastValidatedCheckpoint(t *testing.T) {
@@ -1124,35 +1093,3 @@ func TestKZGCommitmentToVersionedHashes(t *testing.T) {
 	require.Equal(t, vhs[0].String(), vh0)
 	require.Equal(t, vhs[1].String(), vh1)
 }
-
-func TestComputePayloadAttribute(t *testing.T) {
-	service, tr := minimalTestService(t, WithPayloadIDCache(cache.NewPayloadIDCache()))
-	ctx := tr.ctx
-
-	st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
-
-	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, Index: 0})
-	// Cache hit, advance state, no fee recipient
-	slot := primitives.Slot(1)
-	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	cfg := &postBlockProcessConfig{
-		ctx:       ctx,
-		blockRoot: [32]byte{'a'},
-	}
-	fcu := &fcuConfig{
-		headState:     st,
-		proposingSlot: slot,
-		headRoot:      [32]byte{},
-	}
-	require.NoError(t, service.computePayloadAttributes(cfg, fcu))
-	require.Equal(t, false, fcu.attributes.IsEmpty())
-	require.Equal(t, params.BeaconConfig().EthBurnAddressHex, common.BytesToAddress(fcu.attributes.SuggestedFeeRecipient()).String())
-
-	// Cache hit, advance state, has fee recipient
-	suggestedAddr := common.HexToAddress("123")
-	service.cfg.TrackedValidatorsCache.Set(cache.TrackedValidator{Active: true, FeeRecipient: primitives.ExecutionAddress(suggestedAddr), Index: 0})
-	service.cfg.PayloadIDCache.Set(slot, [32]byte{}, [8]byte{})
-	require.NoError(t, service.computePayloadAttributes(cfg, fcu))
-	require.Equal(t, false, fcu.attributes.IsEmpty())
-	require.Equal(t, suggestedAddr, common.BytesToAddress(fcu.attributes.SuggestedFeeRecipient()))
-}
--- a/Show More
+++ b/Show More
@@ -1 +1 @@
 .1.0
 .4.0