diff -r b962ae0a0a05 -r 693b856a4d45 mercurial/sslutil.py
--- a/mercurial/sslutil.py	Thu Apr 28 16:38:15 2016 -0500
+++ b/mercurial/sslutil.py	Sat Apr 30 09:26:47 2016 -0700
@@ -120,9 +120,6 @@
       server (and client) support SNI, this tells the server which certificate
       to use.
     """
-    if not serverhostname:
-        raise error.Abort('serverhostname argument required')
-
     # Despite its name, PROTOCOL_SSLv23 selects the highest protocol
     # that both ends support, including TLS protocols. On legacy stacks,
     # the highest it likely goes in TLS 1.0. On modern stacks, it can