diff --git a/vncdotool/rfb.py b/vncdotool/rfb.py
index <HASH>..<HASH> 100644
--- a/vncdotool/rfb.py
+++ b/vncdotool/rfb.py
@@ -129,7 +129,7 @@ class RFBClient(Protocol):
                 #~ print "rfb"
                 maj, min = [int(x) for x in buffer[3:-1].split('.')]
                 #~ print maj, min
-                if (maj, min) not in [(3,3), (3,7), (3,8)]:
+                if (maj, min) not in [(3,3), (3,7), (3,8), (4,0)]:
                     log.msg("wrong protocol version\n")
                     self.transport.loseConnection()
             buffer = buffer[12:]
rfb: give VNC <I> a chance

  - untested due to lack of access to <I> servers