diff -r 89556caf3c66 -r c814101560d9 mercurial/upgrade_utils/actions.py
--- a/mercurial/upgrade_utils/actions.py	Wed May 31 16:04:16 2023 +0100
+++ b/mercurial/upgrade_utils/actions.py	Wed May 31 18:08:56 2023 +0100
@@ -950,9 +950,6 @@
     requirements in the returned set.
     """
     return {
-        # The upgrade code does not yet support these experimental features.
-        # This is an artificial limitation.
-        requirements.TREEMANIFEST_REQUIREMENT,
         # This was a precursor to generaldelta and was never enabled by default.
         # It should (hopefully) not exist in the wild.
         b'parentdelta',
@@ -1052,6 +1049,7 @@
         requirements.SHARESAFE_REQUIREMENT,
         requirements.SPARSEREVLOG_REQUIREMENT,
         requirements.STORE_REQUIREMENT,
+        requirements.TREEMANIFEST_REQUIREMENT,
         requirements.NARROW_REQUIREMENT,
     }
     for name in compression.compengines: