diff --git a/rpc-client-api/src/request.rs b/rpc-client-api/src/request.rs
index 1bcc42179d96ec..f26024e7afbb19 100644
--- a/rpc-client-api/src/request.rs
+++ b/rpc-client-api/src/request.rs
@@ -8,7 +8,9 @@ use {
 
 #[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
 pub enum RpcRequest {
-    Custom { method: &'static str },
+    Custom {
+        method: &'static str,
+    },
     DeregisterNode,
     GetAccountInfo,
     GetBalance,
@@ -48,6 +50,10 @@ pub enum RpcRequest {
     GetStorageTurn,
     GetStorageTurnRate,
     GetSlotsPerSegment,
+    #[deprecated(
+        since = "1.18.18",
+        note = "Do not use; getStakeActivation is not supported by the JSON-RPC server."
+    )]
     GetStakeActivation,
     GetStakeMinimumDelegation,
     GetStoragePubkeysForSlot,
diff --git a/rpc-client/src/nonblocking/rpc_client.rs b/rpc-client/src/nonblocking/rpc_client.rs
index 45509b4bb3ddc2..532b6176032e5e 100644
--- a/rpc-client/src/nonblocking/rpc_client.rs
+++ b/rpc-client/src/nonblocking/rpc_client.rs
@@ -2082,6 +2082,7 @@ impl RpcClient {
                 use the stake account and StakeHistory sysvar to call \
                 `Delegation::stake_activating_and_deactivating()` instead"
     )]
+    #[allow(deprecated)]
     pub async fn get_stake_activation(
         &self,
         stake_account: Pubkey,