diff --git a/specs/altair/fork.md b/specs/altair/fork.md
index 6228022b8..bf8499a21 100644
--- a/specs/altair/fork.md
+++ b/specs/altair/fork.md
@@ -7,6 +7,9 @@
 
 - [Introduction](#introduction)
 - [Configuration](#configuration)
+- [Helper functions](#helper-functions)
+  - [Misc](#misc)
+    - [`compute_fork_version`](#compute_fork_version)
 - [Fork to Altair](#fork-to-altair)
   - [Fork trigger](#fork-trigger)
   - [Upgrading the state](#upgrading-the-state)
@@ -26,6 +29,22 @@ Warning: this configuration is not definitive.
 | `ALTAIR_FORK_VERSION` | `Version('0x01000000')` |
 | `ALTAIR_FORK_EPOCH` | `Epoch(74240)` (Oct 27, 2021, 10:56:23am UTC) |
 
+## Helper functions
+
+### Misc
+
+#### `compute_fork_version`
+
+```python
+def compute_fork_version(epoch: Epoch) -> Version:
+    """
+    Return the fork version at the given ``epoch``.
+    """
+    if epoch >= ALTAIR_FORK_EPOCH:
+        return ALTAIR_FORK_VERSION
+    return GENESIS_FORK_VERSION
+```
+
 ## Fork to Altair
 
 ### Fork trigger
diff --git a/specs/altair/sync-protocol.md b/specs/altair/sync-protocol.md
index 1aa9316d3..a3b10efa2 100644
--- a/specs/altair/sync-protocol.md
+++ b/specs/altair/sync-protocol.md
@@ -71,8 +71,6 @@ class LightClientUpdate(Container):
     finality_branch: Vector[Bytes32, floorlog2(FINALIZED_ROOT_INDEX)]
     # Sync committee aggregate signature
     sync_aggregate: SyncAggregate
-    # Fork version for the aggregate signature
-    fork_version: Version
     # Slot at which the aggregate signature was created (untrusted)
     signature_slot: Slot
 ```
@@ -211,7 +209,8 @@ def validate_light_client_update(store: LightClientStore,
         pubkey for (bit, pubkey) in zip(sync_aggregate.sync_committee_bits, sync_committee.pubkeys)
         if bit
     ]
-    domain = compute_domain(DOMAIN_SYNC_COMMITTEE, update.fork_version, genesis_validators_root)
+    fork_version = compute_fork_version(compute_epoch_at_slot(update.signature_slot))
+    domain = compute_domain(DOMAIN_SYNC_COMMITTEE, fork_version, genesis_validators_root)
     signing_root = compute_signing_root(update.attested_header, domain)
     assert bls.FastAggregateVerify(participant_pubkeys, signing_root, sync_aggregate.sync_committee_signature)
 ```
diff --git a/specs/bellatrix/fork.md b/specs/bellatrix/fork.md
index 8cb34099b..5c0e174da 100644
--- a/specs/bellatrix/fork.md
+++ b/specs/bellatrix/fork.md
@@ -9,6 +9,9 @@
 
 - [Introduction](#introduction)
 - [Configuration](#configuration)
+- [Helper functions](#helper-functions)
+  - [Misc](#misc)
+    - [Modified `compute_fork_version`](#modified-compute_fork_version)
 - [Fork to Bellatrix](#fork-to-bellatrix)
   - [Fork trigger](#fork-trigger)
   - [Upgrading the state](#upgrading-the-state)
@@ -28,6 +31,24 @@ Warning: this configuration is not definitive.
 | `BELLATRIX_FORK_VERSION` | `Version('0x02000000')` |
 | `BELLATRIX_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
 
+## Helper functions
+
+### Misc
+
+#### Modified `compute_fork_version`
+
+```python
+def compute_fork_version(epoch: Epoch) -> Version:
+    """
+    Return the fork version at the given ``epoch``.
+    """
+    if epoch >= BELLATRIX_FORK_EPOCH:
+        return BELLATRIX_FORK_VERSION
+    if epoch >= ALTAIR_FORK_EPOCH:
+        return ALTAIR_FORK_VERSION
+    return GENESIS_FORK_VERSION
+```
+
 ## Fork to Bellatrix
 
 ### Fork trigger
diff --git a/specs/capella/fork.md b/specs/capella/fork.md
index 0d8283e56..c22387ee7 100644
--- a/specs/capella/fork.md
+++ b/specs/capella/fork.md
@@ -7,6 +7,9 @@
 
 - [Introduction](#introduction)
 - [Configuration](#configuration)
+- [Helper functions](#helper-functions)
+  - [Misc](#misc)
+    - [Modified `compute_fork_version`](#modified-compute_fork_version)
 - [Fork to Capella](#fork-to-capella)
   - [Fork trigger](#fork-trigger)
   - [Upgrading the state](#upgrading-the-state)
@@ -27,6 +30,26 @@ Warning: this configuration is not definitive.
 | `CAPELLA_FORK_EPOCH` | `Epoch(18446744073709551615)` **TBD** |
 
 
+## Helper functions
+
+### Misc
+
+#### Modified `compute_fork_version`
+
+```python
+def compute_fork_version(epoch: Epoch) -> Version:
+    """
+    Return the fork version at the given ``epoch``.
+    """
+    if epoch >= CAPELLA_FORK_EPOCH:
+        return CAPELLA_FORK_VERSION
+    if epoch >= BELLATRIX_FORK_EPOCH:
+        return BELLATRIX_FORK_VERSION
+    if epoch >= ALTAIR_FORK_EPOCH:
+        return ALTAIR_FORK_VERSION
+    return GENESIS_FORK_VERSION
+```
+
 ## Fork to Capella
 
 ### Fork trigger
diff --git a/tests/core/pyspec/eth2spec/test/altair/unittests/test_config_override.py b/tests/core/pyspec/eth2spec/test/altair/unittests/test_config_override.py
index f1503c39f..5c940eafc 100644
--- a/tests/core/pyspec/eth2spec/test/altair/unittests/test_config_override.py
+++ b/tests/core/pyspec/eth2spec/test/altair/unittests/test_config_override.py
@@ -1,4 +1,9 @@
-from eth2spec.test.context import spec_configured_state_test, with_phases
+from eth2spec.test.context import (
+    spec_configured_state_test,
+    spec_state_test_with_matching_config,
+    with_all_phases,
+    with_phases
+)
 from eth2spec.test.helpers.constants import ALTAIR
 
 
@@ -17,3 +22,28 @@ def test_config_override(spec, state):
     # TODO: it would be nice if the create_genesis_state actually outputs a state
     #  for the fork with a slot that matches at least the fork boundary.
     # assert spec.get_current_epoch(state) >= 4
+
+
+@with_all_phases
+@spec_state_test_with_matching_config
+def test_override_config_fork_epoch(spec, state):
+    if state.fork.current_version == spec.config.GENESIS_FORK_VERSION:
+        return
+
+    assert spec.config.ALTAIR_FORK_EPOCH == spec.GENESIS_EPOCH
+    if state.fork.current_version == spec.config.ALTAIR_FORK_VERSION:
+        return
+
+    assert spec.config.BELLATRIX_FORK_EPOCH == spec.GENESIS_EPOCH
+    if state.fork.current_version == spec.config.BELLATRIX_FORK_VERSION:
+        return
+
+    assert spec.config.CAPELLA_FORK_EPOCH == spec.GENESIS_EPOCH
+    if state.fork.current_version == spec.config.CAPELLA_FORK_VERSION:
+        return
+
+    assert spec.config.SHARDING_FORK_EPOCH == spec.GENESIS_EPOCH
+    if state.fork.current_version == spec.config.SHARDING_FORK_VERSION:
+        return
+
+    assert False  # Fork is missing
diff --git a/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py b/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py
index 6411ecb6a..69d9db0f2 100644
--- a/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py
+++ b/tests/core/pyspec/eth2spec/test/altair/unittests/test_sync_protocol.py
@@ -1,7 +1,7 @@
 from copy import deepcopy
 
 from eth2spec.test.context import (
-    spec_state_test,
+    spec_state_test_with_matching_config,
     with_presets,
     with_altair_and_later,
 )
@@ -25,7 +25,7 @@ from eth2spec.test.helpers.merkle import build_proof
 
 
 @with_altair_and_later
-@spec_state_test
+@spec_state_test_with_matching_config
 def test_process_light_client_update_not_timeout(spec, state):
     store = initialize_light_client_store(spec, state)
 
@@ -41,7 +41,7 @@ def test_process_light_client_update_not_timeout(spec, state):
     )
 
     # Sync committee signing the block_header
-    sync_aggregate, fork_version, signature_slot = get_sync_aggregate(spec, state, block_header)
+    sync_aggregate, signature_slot = get_sync_aggregate(spec, state, block_header)
     next_sync_committee_branch = [spec.Bytes32() for _ in range(spec.floorlog2(spec.NEXT_SYNC_COMMITTEE_INDEX))]
 
     # Ensure that finality checkpoint is genesis
@@ -57,7 +57,6 @@ def test_process_light_client_update_not_timeout(spec, state):
         finalized_header=finality_header,
         finality_branch=finality_branch,
         sync_aggregate=sync_aggregate,
-        fork_version=fork_version,
         signature_slot=signature_slot,
     )
 
@@ -72,7 +71,7 @@ def test_process_light_client_update_not_timeout(spec, state):
 
 
 @with_altair_and_later
-@spec_state_test
+@spec_state_test_with_matching_config
 @with_presets([MINIMAL], reason="too slow")
 def test_process_light_client_update_at_period_boundary(spec, state):
     store = initialize_light_client_store(spec, state)
@@ -94,7 +93,7 @@ def test_process_light_client_update_at_period_boundary(spec, state):
     )
 
     # Sync committee signing the block_header
-    sync_aggregate, fork_version, signature_slot = get_sync_aggregate(spec, state, block_header)
+    sync_aggregate, signature_slot = get_sync_aggregate(spec, state, block_header)
     next_sync_committee_branch = [spec.Bytes32() for _ in range(spec.floorlog2(spec.NEXT_SYNC_COMMITTEE_INDEX))]
 
     # Finality is unchanged
@@ -108,7 +107,6 @@ def test_process_light_client_update_at_period_boundary(spec, state):
         finalized_header=finality_header,
         finality_branch=finality_branch,
         sync_aggregate=sync_aggregate,
-        fork_version=fork_version,
         signature_slot=signature_slot,
     )
 
@@ -123,7 +121,7 @@ def test_process_light_client_update_at_period_boundary(spec, state):
 
 
 @with_altair_and_later
-@spec_state_test
+@spec_state_test_with_matching_config
 @with_presets([MINIMAL], reason="too slow")
 def test_process_light_client_update_timeout(spec, state):
     store = initialize_light_client_store(spec, state)
@@ -145,7 +143,7 @@ def test_process_light_client_update_timeout(spec, state):
     )
 
     # Sync committee signing the block_header
-    sync_aggregate, fork_version, signature_slot = get_sync_aggregate(spec, state, block_header)
+    sync_aggregate, signature_slot = get_sync_aggregate(spec, state, block_header)
 
     # Sync committee is updated
     next_sync_committee_branch = build_proof(state.get_backing(), spec.NEXT_SYNC_COMMITTEE_INDEX)
@@ -160,7 +158,6 @@ def test_process_light_client_update_timeout(spec, state):
         finalized_header=finality_header,
         finality_branch=finality_branch,
         sync_aggregate=sync_aggregate,
-        fork_version=fork_version,
         signature_slot=signature_slot,
     )
 
@@ -175,7 +172,7 @@ def test_process_light_client_update_timeout(spec, state):
 
 
 @with_altair_and_later
-@spec_state_test
+@spec_state_test_with_matching_config
 @with_presets([MINIMAL], reason="too slow")
 def test_process_light_client_update_finality_updated(spec, state):
     store = initialize_light_client_store(spec, state)
@@ -211,7 +208,7 @@ def test_process_light_client_update_finality_updated(spec, state):
     )
 
     # Sync committee signing the block_header
-    sync_aggregate, fork_version, signature_slot = get_sync_aggregate(spec, state, block_header)
+    sync_aggregate, signature_slot = get_sync_aggregate(spec, state, block_header)
 
     update = spec.LightClientUpdate(
         attested_header=block_header,
@@ -220,7 +217,6 @@ def test_process_light_client_update_finality_updated(spec, state):
         finalized_header=finalized_block_header,
         finality_branch=finality_branch,
         sync_aggregate=sync_aggregate,
-        fork_version=fork_version,
         signature_slot=signature_slot,
     )
 
diff --git a/tests/core/pyspec/eth2spec/test/context.py b/tests/core/pyspec/eth2spec/test/context.py
index 35e4f1bcb..06313c195 100644
--- a/tests/core/pyspec/eth2spec/test/context.py
+++ b/tests/core/pyspec/eth2spec/test/context.py
@@ -277,6 +277,39 @@ def spec_configured_state_test(conf):
     return decorator
 
 
+def config_fork_epoch_overrides(spec, state):
+    overrides = {}
+    if state.fork.current_version == spec.config.GENESIS_FORK_VERSION:
+        pass
+    elif state.fork.current_version == spec.config.ALTAIR_FORK_VERSION:
+        overrides['ALTAIR_FORK_EPOCH'] = spec.GENESIS_EPOCH
+    elif state.fork.current_version == spec.config.BELLATRIX_FORK_VERSION:
+        overrides['ALTAIR_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['BELLATRIX_FORK_EPOCH'] = spec.GENESIS_EPOCH
+    elif state.fork.current_version == spec.config.CAPELLA_FORK_VERSION:
+        overrides['ALTAIR_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['BELLATRIX_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['CAPELLA_FORK_EPOCH'] = spec.GENESIS_EPOCH
+    elif state.fork.current_version == spec.config.SHARDING_FORK_VERSION:
+        overrides['ALTAIR_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['BELLATRIX_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['CAPELLA_FORK_EPOCH'] = spec.GENESIS_EPOCH
+        overrides['SHARDING_FORK_EPOCH'] = spec.GENESIS_EPOCH
+    else:
+        assert False  # Fork is missing
+    return overrides
+
+
+def spec_state_test_with_matching_config(fn):
+    def decorator(fn):
+        def wrapper(*args, spec: Spec, **kw):
+            conf = config_fork_epoch_overrides(spec, kw['state'])
+            overrides = with_config_overrides(conf)
+            return overrides(fn)(*args, spec=spec, **kw)
+        return wrapper
+    return spec_test(with_state(decorator(single_phase(fn))))
+
+
 def expect_assertion_error(fn):
     bad = False
     try:
diff --git a/tests/core/pyspec/eth2spec/test/helpers/light_client.py b/tests/core/pyspec/eth2spec/test/helpers/light_client.py
index b35c6c687..7dcad319a 100644
--- a/tests/core/pyspec/eth2spec/test/helpers/light_client.py
+++ b/tests/core/pyspec/eth2spec/test/helpers/light_client.py
@@ -45,5 +45,4 @@ def get_sync_aggregate(spec, state, block_header, signature_slot=None):
         sync_committee_bits=sync_committee_bits,
         sync_committee_signature=sync_committee_signature,
     )
-    fork_version = signature_state.fork.current_version
-    return sync_aggregate, fork_version, signature_slot
+    return sync_aggregate, signature_slot