diff -r 60d396d3da80 -r d725fe3e3989 hgext3rd/topic/discovery.py
--- a/hgext3rd/topic/discovery.py	Wed Apr 18 22:36:54 2018 -0700
+++ b/hgext3rd/topic/discovery.py	Thu Apr 19 10:50:24 2018 +0200
@@ -11,9 +11,14 @@
     exchange,
     extensions,
     util,
-    wireproto,
 )
 
+try:
+    from mercurial import wireproto
+    wireproto.branchmap
+except ImportError: # <= hg-4.5
+    from mercurial import wireprotov1server as wireproto
+
 def _headssummary(orig, *args):
     # In mercurial < 4.2, we receive repo, remote and outgoing as arguments
     pushop = None