diff -r 91db2aa0edfe -r cfb227016d01 mercurial/chgserver.py
--- a/mercurial/chgserver.py	Sun Dec 04 23:22:34 2016 +0530
+++ b/mercurial/chgserver.py	Mon Dec 05 21:36:35 2016 +0000
@@ -255,7 +255,7 @@
 def _loadnewui(srcui, args):
     from . import dispatch  # avoid cycle
 
-    newui = srcui.__class__()
+    newui = srcui.__class__.load()
     for a in ['fin', 'fout', 'ferr', 'environ']:
         setattr(newui, a, getattr(srcui, a))
     if util.safehasattr(srcui, '_csystem'):