WMQ v5.3 FP14 is now available for iSeries.
The Group PTFs have been updated and all relevant webpages have been published. The download is available through Fix Central.
Please see the "Recommended Fixes for Websphere MQ website -> http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037#2 for more information. This is the last planned Fix Pack for WMQ v5.3.