On november 22nd 2012, the PHP group has released PHP 5.4.9 and PHP 5.3.19, that bring ~15 bug fixes. The corresponding packages are now available on Dotdeb for Debian 6.0 “Squeeze” on both amd64 and i386 architectures.
Please also note that Xcache (packaged as php5-xcache) has been upgraded to its 3.0.0 version.
As usual, please read the ChangeLog before upgrading and be sure to use to the latest packages before reporting any issue.