--- a/mercurial/configitems.py	Fri Jan 08 18:07:33 2021 +0530
+++ b/mercurial/configitems.py	Fri Jan 08 21:34:16 2021 +0530
@@ -1084,6 +1084,11 @@
 )
 coreconfigitem(
     b'experimental',
+    b'sharesafe-warn-outdated-shares',
+    default=True,
+)
+coreconfigitem(
+    b'experimental',
     b'single-head-per-branch',
     default=False,
 )