On php.net, we can read : All users of PHP are encouraged to upgrade to PHP 5.4.6, or at least 5.3.16.
Does it mean that it is better to use 5.4.6 than 5.3.16, even for production ?
I have heard that 5.4.6 is not stable.
I would be interested in 5.4.6 in order to use http://php.net/manual/en/session.upload-progress.php, but will not if PHP 5.4.6 is not stable.
For developing a new project from scratch, I would go with 5.4. It will have a much longer shelf life than 5.3 or prior versions.
For deploying an existing project, including any open source PHP code you downloaded from the Internet, I would use PHP 5.3. The reason for this is that 5.4 has a few places where backward compatibility was broken, and some existing PHP scripts will need updating to be compatible with 5.4. In a few cases, the package would have to be completely refactored to work with 5.4.
See the PHP 5.4 migration guide for all the gory details.
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.