diff -r 59f1e33f74a6 -r 5b60f7d652f2 mercurial/extensions.py
--- a/mercurial/extensions.py	Fri May 11 21:53:26 2018 +0900
+++ b/mercurial/extensions.py	Thu May 03 18:13:43 2018 +0900
@@ -696,7 +696,7 @@
             ext = findcmd(cmd, name, path)
             if ext:
                 break
-    if ext and 'DEPRECATED' not in ext.__doc__:
+    if ext:
         return ext
 
     raise error.UnknownCommand(cmd)