4.1.0 release notes: correct a confusing typo

(cherry picked from commit 812d51b)

Author: michaelklishin

release-notes/4.1.0.md

@@ -115,7 +115,7 @@ None. The required feature flag set is the same as in `4.0.x`.
 ### Mixed version cluster compatibility
 
 RabbitMQ 4.1.0 nodes can run alongside `4.0.x` nodes. `4.1.x`-specific features can only be made available when all nodes in the cluster
-upgrade to 4.0.0 or a later patch release in the new series.
+upgrade to 4.1.0 or a later patch release in the new series.
 
 While operating in mixed version mode, some aspects of the system may not behave as expected. The list of known behavior changes will be covered in future updates.
 Once all nodes are upgraded to 4.1.0, these irregularities will go away.