Wayne wrote:
Required by the Web host actually. PHP 4 was discontinued 3 years ago in favor of PHP 5 and the support path for PHP4 has now ended.
You might have considered this already, but if there is a demand to keep the site running "as is" I can recommend using a web hosting with virtual server (or dedicated server) and just install exactly what you need as "root" (eg. PHP4), not to mention the freedom to offer other services (besides web) to the Amiga community.
There are some benefits using old software on a web server in my opinion:
* Old software usually runs faster and less memory hungry.
* Keeping a system up to date for security is needed in new systems where evil hackers are active, while the really old stuff are reasonably safe. I guess the kids just don't know how to exploit them anymore.

* Old PHP sources are usually easy to edit and maintain yourself, just make changes as you see fit in a system you know everything about. Good luck doing that with the new stuff coded in an object oriented fashion.
* Needless to mention, old unsupported software doesn't require updates. Lovely to be the lazy admin, right?

I write this out of experience from taking care of my own web site
www.eurasia.nu since 2002 (which once was a php nuke 5.6 long time ago, before I started customizing most of the PHP code).