diff --git a/remotefilelog/__init__.py b/remotefilelog/__init__.py
--- a/remotefilelog/__init__.py
+++ b/remotefilelog/__init__.py
@@ -116,11 +116,7 @@
 testedwith = 'ships-with-fb-hgext'
 
 repoclass = localrepo.localrepository
-if util.safehasattr(repoclass, '_basesupported'):
-    repoclass._basesupported.add(shallowrepo.requirement)
-else:
-    # hg <= 2.7
-    repoclass.supported.add(shallowrepo.requirement)
+repoclass._basesupported.add(shallowrepo.requirement)
 
 def uisetup(ui):
     """Wraps user facing Mercurial commands to swap them out with shallow