Jordi Boggiano, the creator and maintainer of Composer and Packagist, released some fresh statistics on which PHP version composer users are running.

A few observations: 5.3 dropped to almost nothing which is great news! 5.4 is also down by almost 10% and is definitely on the way out. 5.5 is still big but less so, while 5.6 got a huge boost to become the main version. The big surprise is that we have 20% of PHP7 already! That is great news only six months after this major release came out.

20% sounds really great, but I suspect that this number is slightly optimistic. Many developers who are running PHP 7 in their dev environment use PHP 5.X in production.

Over on the package side only ±20% of all packages require PHP 5.5 or above and only 1% requires PHP 7. Jordi has this to say about that:

All in all, it seems like package requires are way behind actual version usage, so I would like to encourage everyone to be a bit more aggressive in bumping PHP requirements when tagging new major releases of their libs.

That's great advice. The bulk of the newly released Spatie packages require PHP 7. In my opinion you'd do our ecosystem a favour by picking PHP 7 as a minimum requirement when you are creating a new package.

Read Jordi's entire post on his blog for more details: https://seld.be/notes/php-versions-stats-2016-1-edition