The last few seconds before projects and Internet hosting companies officially support PHP 5.2 via GoPHP5.org.

Therefore, the listed software projects have all agreed that effective February 5th, 2008, any new feature releases will have a minimum version requirement of at least PHP 5.2.0. Furthermore, the listed web hosts have agreed that effective February 5th, 2008, they will include PHP 5.2 (or a more recent version) in their service offer.

If your PHP-based software or Web server still does not support PHP 5, I would conclude they are living in the past. I personally would be looking for something with a better vision of the future...