upgrading PHP from 4.3.2...

[GrendelKhan{TSU]

Ok. I'm helping upgrade a forum for a friend from 3.0.6 to current... but realized they are on PHP 4.3.2 and so I need to upgrade PHP first before I attempt a vbulletin upgrade. So my question is straightforward if not simple:

How do I upgrade PHP? How do i do so without messing up the forum?
anything special considerations I need to take beforehand?

Any help would be great appreciated. :)

[Paul M]

The answer to that depends on many things, the most obvious being the server OS.