Added the versionadded directive

Author: javiereguiluz

workflow.rst

@@ -334,10 +334,14 @@ order:
     * ``workflow.[workflow name].announce``
     * ``workflow.[workflow name].announce.[transition name]``
 
-    You can avoid those events by using the context::
+    You can avoid triggering those events by using the context::
 
         $workflow->apply($subject, $transitionName, [Workflow::DISABLE_ANNOUNCE_EVENT => true]);
 
+    .. versionadded:: 5.1
+
+        The ``Workflow::DISABLE_ANNOUNCE_EVENT`` constant was introduced in Symfony 5.1.
+
 .. note::
 
     The leaving and entering events are triggered even for transitions that stay