diff --git a/specs/eip4844/p2p-interface.md b/specs/eip4844/p2p-interface.md
index b431b7927..392dc589a 100644
--- a/specs/eip4844/p2p-interface.md
+++ b/specs/eip4844/p2p-interface.md
@@ -131,6 +131,7 @@ Per `context = compute_fork_digest(fork_version, genesis_validators_root)`:
 **Protocol ID:** `/eth2/beacon_chain/req/beacon_blocks_by_root/2/`
 
 After `EIP4844_FORK_EPOCH`, `BeaconBlocksByRootV2` is replaced by `BeaconBlockAndBlobsSidecarByRootV1`
+clients MUST support requesting blocks by root for pre-fork-epoch blocks.
 
 Per `context = compute_fork_digest(fork_version, genesis_validators_root)`: