diff -r 16203c6079e7 -r 5890e5872f36 mercurial/hgweb/server.py
--- a/mercurial/hgweb/server.py	Tue Mar 13 08:58:52 2018 -0700
+++ b/mercurial/hgweb/server.py	Tue Mar 13 09:45:56 2018 -0700
@@ -231,6 +231,11 @@
             self.wfile.write('0\r\n\r\n')
             self.wfile.flush()
 
+    def version_string(self):
+        if self.server.serverheader:
+            return self.server.serverheader
+        return httpservermod.basehttprequesthandler.version_string(self)
+
 class _httprequesthandlerssl(_httprequesthandler):
     """HTTPS handler based on Python's ssl module"""
 
@@ -304,6 +309,8 @@
         self.addr, self.port = self.socket.getsockname()[0:2]
         self.fqaddr = socket.getfqdn(addr[0])
 
+        self.serverheader = ui.config('web', 'server-header')
+
 class IPv6HTTPServer(MercurialHTTPServer):
     address_family = getattr(socket, 'AF_INET6', None)
     def __init__(self, *args, **kwargs):