This update is a fix for a vulnerability that was recently discovered in PHPs openssl_x509_parse() function (CVE-2013-6420).  The problem affects all versions of PHP (5.2, 5.3 and 5.4).   Customers who may be using this function to load untrusted (remote) certificates should upgrade as soon as possible. 
Also included is a fix for a problem that could result in PHP extension settings not being properly replicated to new nodes joining the cluster.
Linux users who wish to update can use their system update manager to obtain the new updates.
Windows and IBM i users can download the updates from the Zend Server downloads page.