Will upgrading PHP "break" anything?

[basa]

I hired a guy to upgrade PHP because of the security concerns posted here in this forum, and now I wonder if I have to do anything with vbulletin. Will upgrading it just work without me changing anything on the server side? What about mysql?

[Steve Machol]

Upgrade to which version? Do you have Zend Optimizer or any accelerators installed? It's certainly possibly a bad or incomplete upgrade could break things.

[basa]

Upgrade to which version? Do you have Zend Optimizer or any accelerators installed? It's certainly possibly a bad or incomplete upgrade could break things.

Hi Steve, thanks for the answer. No Zend Optimizer that I know of, and no accelrators. Just plain vanilla. I assume that a bad upgrade would break it, but I hope that's not case ;). If all goes well it should work and require nothing from vbulletin, right?