diff -r 3941fe53670d -r ee91966aec0f mercurial/exchangev2.py
--- a/mercurial/exchangev2.py	Thu Feb 18 15:07:45 2021 +0100
+++ b/mercurial/exchangev2.py	Wed Mar 03 14:00:45 2021 +0100
@@ -22,6 +22,7 @@
     narrowspec,
     phases,
     pycompat,
+    requirements as requirementsmod,
     setdiscovery,
 )
 from .interfaces import repository
@@ -183,7 +184,7 @@
 
     # TODO This is super hacky. There needs to be a storage API for this. We
     # also need to check for compatibility with the remote.
-    if b'revlogv1' not in repo.requirements:
+    if requirementsmod.REVLOGV1_REQUIREMENT not in repo.requirements:
         return False
 
     return True