I have a similar problem but minor compared to what some will be having on large sites. I have a server with both 4 and 5 but mostly 4 codebase. There&#39;s about a dozen virtual hosts that need to be got\ten up to speed.<br>
<br>My appraoch is is to build a second server on an old box, mirroring everything in the web root but with only php5 running and that way I&#39;ll see what will break before doing the real thing.<br>