diff -r 468e451fc0de -r 6c84fc9c9a90 mercurial/requirements.py
--- a/mercurial/requirements.py	Tue May 04 05:18:57 2021 +0200
+++ b/mercurial/requirements.py	Mon Mar 29 22:40:54 2021 +0200
@@ -30,6 +30,10 @@
 
 # Increment the sub-version when the revlog v2 format changes to lock out old
 # clients.
+CHANGELOGV2_REQUIREMENT = b'exp-changelog-v2'
+
+# Increment the sub-version when the revlog v2 format changes to lock out old
+# clients.
 REVLOGV2_REQUIREMENT = b'exp-revlogv2.2'
 
 # A repository with the sparserevlog feature will have delta chains that