diff --git a/remotefilelog/remotefilelogserver.py b/remotefilelog/remotefilelogserver.py
--- a/remotefilelog/remotefilelogserver.py
+++ b/remotefilelog/remotefilelogserver.py
@@ -79,7 +79,10 @@
             changedfiles = list([f for f in changedfiles if not m(f)])
         return orig(self, changedfiles, linknodes, commonrevs, source)
 
-    wrapfunction(changegroup.cg1packer, 'generatefiles', generatefiles)
+    if util.safehasattr(changegroup, 'cgpacker'):
+        wrapfunction(changegroup.cgpacker, 'generatefiles', generatefiles)
+    else:
+        wrapfunction(changegroup.cg1packer, 'generatefiles', generatefiles)
 
 onetime = False
 def onetimesetup(ui):