[FIXED JENKINS-33319] Fix up @since tags post merge

core/src/main/java/hudson/TcpSlaveAgentListener.java

@@ -204,7 +204,7 @@ public final class TcpSlaveAgentListener extends Thread {
      * This extension provides a Ping protocol that allows people to verify that the TcpSlaveAgentListener is alive.
      * We also use this to wake the acceptor thread on termination.
      *
-     * @since TODO
+     * @since 1.653
      */
     @Extension
     public static class PingAgentProtocol extends AgentProtocol {