diff -r f0297263a1e8 Lib/ssl.py
--- a/Lib/ssl.py	Fri Dec 12 12:27:08 2014 +0100
+++ b/Lib/ssl.py	Fri Dec 12 12:28:42 2014 +0100
@@ -922,11 +922,16 @@ def PEM_cert_to_DER_cert(pem_cert_string
     d = pem_cert_string.strip()[len(PEM_HEADER):-len(PEM_FOOTER)]
     return base64.decodebytes(d.encode('ASCII', 'strict'))
 
-def get_server_certificate(addr, ssl_version=PROTOCOL_SSLv3, ca_certs=None):
+def get_server_certificate(addr, ssl_version=None, ca_certs=None):
     """Retrieve the certificate from the server at the specified address,
     and return it as a PEM-encoded string.
     If 'ca_certs' is specified, validate the server cert against it.
     If 'ssl_version' is specified, use it in the connection attempt."""
+    if ssl_version is None:
+        try:
+            ssl_version = PROTOCOL_SSLv3
+        except NameError:
+            ssl_version = PROTOCOL_SSLv23
 
     host, port = addr
     if ca_certs is not None: