8/8/08 marked the final day that PHP4 would receive support from it’s developers, and 4.4.9 marks the final update it will receive. It’s an end to an era, really; the first version of PHP4 was released in 2000. Even while PHP5 was released 4 years ago, and PHP6′s release is looming on the horizon, web hosts have been slow to adopt the new versions due to concerns of compatibility issues. I don’t think they’ll have much option, now.
That’s a good thing, in my book. PHP5 introduced a whole slew of great new features, and PHP6 is shaping up to be a wonderful upgrade as well. The only loss over PHP4 is limited compatibility with old scripts, but to be quite frank the scripts that break under that upgrade are ones you should be concerned about using in the first place. Namely, much of the methods PHP5 revokes that breaks those PHP4 scripts are due to security and performance concerns.
PHP5 has improved OOP support, better security and better performance. Do yourself a favor and upgrade already.