Yesterday, I upgraded the PHP version on my server from 5.2.4 to 5.2.5. PHP 5.2.5 brings improved "stability of the PHP 5.2.x branch with over 60 bug fixes, several of which are security related". I also reintroduced eAccelerator back onto the server. I stopped using eAccelerator last spring, not so much because I had any real issues with it, but because I spent the summer months hosting my sites on the cheap.
This time, when I compiled the new version of PHP 5.2 onto my server, I also made the decision to not load the latest version of PHP 4. Although most of the Web applications I run on the server are PHP 5 compatible, I've always made sure I also had access to a version of PHP 4. The time has finally come though where I really don't have a need or desire to host a content management system that is only PHP 4 compatible.
If your CMS is not compatible with PHP 5, I think this is the time you should begin to start asking why it isn't compatible with the latest version of PHP. Not only is there a lot of community effort going on through GoPHP5 to get hosting services to provide PHP 5 on their Web servers, PHP 4's days are coming to a close. At the end of this year (2007), the PHP development team will no longer be supporting new releases of PHP 4.4. By August 2008, no critical security fixes will be provided for PHP 4. It just makes sense to me that this is the ideal moment of opportunity to start moving your Web applications off of PHP 4 only servers.
Now that I'm running only PHP 5 on the server, I feel as if my life just got simpler. Trying to remember what was needed for Linux and Apache to support both PHP 4 and PHP 5 wasn't difficult, but it was annoying. I spend too much time as it is keeping track of the clutter in my head. At least for when it comes to PHP, I finally only need to worry about PHP 5. Good riddance PHP 4!