our ipv6 support patch is already merged in python-memcached 1.50 or later.

stack/erp5/buildout.cfg

@@ -610,9 +610,6 @@ Products.PluggableAuthService = 1.9.0
 # --library-dirs, so we use our modified version
 pysvn = 1.7.4nxd006
 
-# modified version to support ipv6
-python-memcached = 1.47-ipv6-1
-
 # use newest version of pytz
 pytz =
 
@@ -698,6 +695,7 @@ psutil = 1.2.1
 pyflakes = 0.7.3
 python-ldap = 2.4.14
 python-magic = 0.4.6
+python-memcached = 1.53
 qrcode = 4.0.4
 requests = 2.2.1
 restkit = 4.2.2