The PHP development team released a new version of the 5.3.x release. Before you upgrade to a 5.3.x release on a production machine, please check if all PHP based apps are supporting 5.3.x as there are some compatibility problems and you might get some strange results. This release focuses on improving the stability of the PHP 5.3.x branch with over 100 bug fixes, some of which are security related. This version introduces a new incompatible change with older versions of 5.3.x which affect the use of namespaces.
During compilations tests I’ve discovered some problems which made it impossible to use it with the mysqli module. The error you would get is:
/usr/local/mysql/include/mysql/my_global.h:1008: error: duplicate ‘unsigned’
/usr/local/mysql/include/mysql/my_global.h:1008: warning: useless type name in empty declaration
make: *** [ext/mysqli/mysqli.lo] Error 1
I’d twittered about it and got a prompt response from Rasmus Lerdorf with a patch which resolves the problem. if you apply the patch before compiling everything will be fine. I would expect that the people at PHP will release an update within a few days.
The problems, bugs and security enhancements which were introduced in 5.3.3 you can read about them in the ChangeLog.
For instructions on how to upgrade PHP please read: Upgrading PHP.