Pawel F wrote:Hi,
At least, I have all good news for you:
1) If you are using Joomla 3.x or Joomla 2.5 - under PHP 5.4 they will be faster and safer a little bit more.
2) But you have to check all installed modules (not GK), because sometime they may need update to new versions.
3) Check if you can also change MySql to MySqli - from Global configuration, if you are using modern version of database
But in most cased all will be smooth without any problems.