Pascal Martin's latest post (in French, but the English version is coming soon) shares some statistics he's gathered around the usage of various software around the web, more specifically those involved in web-based applications.

I've collected statistics about the use of different PHP versions several times. The first time was in September 2011 and the most recent was in November 2013. At this point, PHP 5.2 still accounted for 34.4% of all PHP installations with PHP 5.3 moving up to 48.7%. This new data was collected the weekend of October 19th, 2014. At this point, the current stable versions of PHP are 5.4.34, 5.5.18 and 5.6.2. PHP 5.3 is no longer maintained (since August 14th 2014) and PHP 5.2 hasn't been supported for 4 years now.

He's broken up the statistics into a few different sections:

• Web server software
• Usage of major versions of PHP
• Usage of minor versions of PHP
• Versions in use under each of the major version numbers

He includes both the raw numbers (percentages) and some graphs showing the results in a bit more consumable fashion. It's interesting to see that, despite it being quite an old version now, PHP 5.3.x still has the largest share in the usage results.

UPDATE: He's posted the English version now as well.