diff --git a/x/staking/types/keys.go b/x/staking/types/keys.go
index 3cc55825a1..4bf3ca0819 100644
--- a/x/staking/types/keys.go
+++ b/x/staking/types/keys.go
@@ -56,6 +56,9 @@ var (
 	ParamsKey = []byte{0x51} // prefix for parameters for module x/staking
 
 	DelegationByValIndexKey = []byte{0x71} // key for delegations by a validator
+
+	// NOTE: keys in range 0x81–0x87 were previously used in liquid staking forks of the staking module.
+	// Module developers MUST NOT use these keys and MUST consider them "reserved".
 )
 
 // UnbondingType defines the type of unbonding operation