Just a little bit slower - if slower at all. Probably nothing to worry about much.

Can't say I've noticed anything, but I'll try to keep an eye on it. Just a little slower or unbearably slow?

I have a feeling that the site (not the forum) is now loading a bit slower than before. But maybe I am wrong as this is my first visit to TGOD for several weeks now.

I just edited the server configuration so that the forum is now running on PHP5 instead of version 4.

The PHP team themselves have announced the end of life for the now seven-year-old version 4, and quite rightly so. There's really no need for it anymore, as PHP 5.2 is now very stable and also quite a lot better

Everything should just continue to work as normal here (on my development system, I had some version of PHP5 installed anyway), but should anything strange happen, please let me know.

P.S. I'll also turn the switch for the site itself in a few days. That code is a lot older (and a lot worse) than the forum code, so it's a little more likely to cause problems there - even though I'm very confident the switch will go smoothly there, too.