--- a/mercurial/wireprotov2server.py	Fri Apr 13 12:49:47 2018 -0700
+++ b/mercurial/wireprotov2server.py	Fri Apr 13 12:50:47 2018 -0700
@@ -19,6 +19,7 @@
     encoding,
     error,
     pycompat,
+    streamclone,
     util,
     wireproto,
     wireprotoframing,
@@ -394,6 +395,10 @@
             'permissions': [entry.permission],
         }
 
+    if streamclone.allowservergeneration(repo):
+        caps['rawrepoformats'] = sorted(repo.requirements &
+                                        repo.supportedformats)
+
     return proto.addcapabilities(repo, caps)
 
 def wireprotocommand(*args, **kwargs):