diff --git a/docs/user-manual/en/message-expiry.md b/docs/user-manual/en/message-expiry.md
index 39a413405c..919dbfd434 100644
--- a/docs/user-manual/en/message-expiry.md
+++ b/docs/user-manual/en/message-expiry.md
@@ -71,7 +71,7 @@ The reaper thread can be configured with the following properties in
 
 -   `message-expiry-thread-priority`
 
-    The reaper thread priority (it must be between 0 and 9, 9 being the
+    The reaper thread priority (it must be between 1 and 10, 10 being the
     highest priority, default is 3)
 
 ## Example