--- a/mercurial/httppeer.py	Fri Apr 06 22:39:58 2018 -0700
+++ b/mercurial/httppeer.py	Thu Jan 18 12:54:01 2018 +0100
@@ -287,7 +287,7 @@
         # Tell the server we accept application/mercurial-0.2 and multiple
         # compression formats if the server is capable of emitting those
         # payloads.
-        protoparams = set()
+        protoparams = {'partial-pull'}
 
         mediatypes = set()
         if self._caps is not None: