diff -r f4dec0cca9a1 -r 84468b90e9c1 server/sources/ldapfeed.py
--- a/server/sources/ldapfeed.py	Wed Sep 16 11:23:51 2015 +0200
+++ b/server/sources/ldapfeed.py	Mon Sep 14 16:03:07 2015 +0200
@@ -21,6 +21,8 @@
 
 from datetime import datetime
 
+from six import string_types
+
 import ldap
 from ldap.ldapobject import ReconnectLDAPObject
 from ldap.filter import filter_format
@@ -376,7 +378,7 @@
                     itemdict[key] = value
         # we expect memberUid to be a list of user ids, make sure of it
         member = self.group_rev_attrs['member']
-        if isinstance(itemdict.get(member), basestring):
+        if isinstance(itemdict.get(member), string_types):
             itemdict[member] = [itemdict[member]]
         return itemdict