diff --git a/specs/merge/beacon-chain.md b/specs/merge/beacon-chain.md
index 364cc4377..043bc2afe 100644
--- a/specs/merge/beacon-chain.md
+++ b/specs/merge/beacon-chain.md
@@ -1,5 +1,7 @@
 # Ethereum 2.0 The Merge
 
+**Warning:** This document is based on [Phase 0](../phase0/beacon-chain.md) and considered to be rebased to [Altair](../altair/beacon-chain.md) once the latter is shipped.
+
 **Notice**: This document is a work-in-progress for researchers and implementers.
 
 ## Table of contents
diff --git a/specs/merge/validator.md b/specs/merge/validator.md
index 75e804187..aff4263b2 100644
--- a/specs/merge/validator.md
+++ b/specs/merge/validator.md
@@ -1,5 +1,7 @@
 # Ethereum 2.0 The Merge
 
+**Warning:** This document is based on [Phase 0](../phase0/validator.md) and considered to be rebased to [Altair](../altair/validator.md) once the latter is shipped.
+
 **Notice**: This document is a work-in-progress for researchers and implementers.
 
 ## Table of contents