With the recent release of PHP 5.2.14 the PHP Team has decided to end active support for this branch of PHP. This means there will be no further active development or bug fixes to this branch of PHP. Instead focus will be on PHP 5.3 and then onto PHP 6.
With many large projects still actively supporting PHP4, the choice is puzzling. A lot of web hosts still haven’t upgraded from PHP 4 based servers due to various incompatibility issues, it can sometimes take weeks or months to test and check all code against the latest versions of PHP when they are released which does hold up rolling out upgrades to live servers, however problems like this shouldn’t hold up the development of PHP.
From the PHP team’s point of view, they can only support a version for a set period of time before it becomes too hard to keep back porting changes to the older releases. PHP 5.2 was released way back in 2006, a lot has changed since then so it isn’t unexpected to retire it now.
If a large package that is commonly used has issues on a certain version of PHP, it will hold back providers from upgrading to that version even if the benefits are there, this is especially true for shared hosting providers who tend to stick with the version that causes them the least problems and support.
There needs to be some changes somewhere to make the constant evolving nature of PHP easier to adopt and web site framework developers really need to evolve with PHP to help speed up the adoption of newer versions on a larger scale than they are (I’m thinking shared hosting providers here).