In this new post to her blog Lorna Mitchell takes a look at some of the current statistics around PHP version adoption - all the way from the ancient 5.0 through the shiny new (upcoming) 5.5 releases.

PHP runs over 75% of all websites whose technologies are known (source: w3techs), which makes for a really REALLY long tail of users who once installed wordpress, phpmyadmin, or some other open source project that helped their business needs at the time. What they don't do is upgrade. PHP's current usage statistics look like this (source and raw numbers are if you want them):

She points out that around half of the results show that sites are running on unsupported versions of PHP (<=5.2) but notes that it's not always their choice. There's lots of factors that play into upgrading these versions that are not always in the user's control (like the speed of distro updates). She covers some of the things that came around in the newer versions of PHP 5.2 and 5.3 including some large performance jumps, especially in 5.4.

In truth, the future is already here for those people on PHP 5.4 and beyond. Keeping PHP upgraded is just part of our regular maintenance workflow, and the language is progressing in regular and manageable steps. If you've been left behind then I strongly recommend that you start making plans for upgrading your platform, or moving to a newer one.

According to this new report on the W3 Techs site, the usage of PHP 5.2 has been passed up by the numbers for the usage of PHP 5.3 (finally).

PHP 5.3 has been released in June 2009, so it took a while to gain that level of popularity. End of support for PHP 5.2 has been declared in December 2010, but is was still the most popular version until now. Version 5.3 will enter the end-of-life cycle in March 2013. Version 5.4, used by only 3.0%, is now considered state-of-the-art.

The numbers have been consistently trending towards intersection with the usage of PHP 5.4 picking up, but no where near the 5.3 and 5.2 numbers. They also point out that PHP version adoption has a history of being slow. Contributing factors to this could be the overall impression of the language and how much "room for improvement" it seems to have.

It's not difficult to predict that PHP as a language will continue to dominate web development in the near future. What will be more exciting is to watch what new versions of PHP will look like.

The main PHP.net site has the release announcement for the two latest versions of the language - PHP 5.3.3 and PHP 5.2.14.

The PHP development team would like to announce the immediate availability of PHP 5.3.3. This release focuses on improving the stability and security of the PHP 5.3.x branch with over 100 bug fixes, some of which are security related. All users are encouraged to upgrade to this release. [...] The PHP development team would like to announce the immediate availability of PHP 5.2.14. This release focuses on improving the stability of the PHP 5.2.x branch with over 60 bug fixes, some of which are security related.

The announcements list some of the major security enhancements and fixes in both new versions as well as a few new features like updates to the PCRE libraries and more.

Note: this PHP 5.2.14 release marks the end of active support for the PHP 5.2.x branch. It is encouraged that you upgrade to PHP 5.3 by following the steps in this migration guide.

As part of a project he was working up, Cory Rauch has created some statistics comparing the performance of the latest PHP 5 series release, PHP 5.2, with the previous version, PHP 5.1.

I can't say the results of the benchmarks are surprising, but it does give a good idea of where, speed-wise, they really improved things in this new release. There are some stats, though, that didn't make that much of a jump. Those seem to be ones dealing with objects and their handling, though - so there's not that much of a jump there anyway.

He tested all sorts of operations, including working with binary data, string and array functionality, looping (for, foreach, etc), and operators. For each statistic, he provides what the test is doing and what the results are. Testing was done with the PHPLens benchmark suite.

As part of a project he was working up, Cory Rauch has created some statistics comparing the performance of the latest PHP 5 series release, PHP 5.2, with the previous version, PHP 5.1.

I can't say the results of the benchmarks are surprising, but it does give a good idea of where, speed-wise, they really improved things in this new release. There are some stats, though, that didn't make that much of a jump. Those seem to be ones dealing with objects and their handling, though - so there's not that much of a jump there anyway.

He tested all sorts of operations, including working with binary data, string and array functionality, looping (for, foreach, etc), and operators. For each statistic, he provides what the test is doing and what the results are. Testing was done with the PHPLens benchmark suite.