A few observations: 5.3 and 5.4 at this point are gone as far as I am concerned! 5.5 still has a good presence but lost 12% in 6 months which is awesome. 5.6 basically stayed stable as I suspect people jumped from 5.5 to 7 directly probably when upgrading Ubuntu LTS. 7.0 gained 15% and is now close to being the most deployed version, 1 year after release! That should definitely encourage more libraries to require it IMO, and I hope it is good encouragement to PHP internals folks as well to see that people actually upgrade these days :)
It's very cool that PHP 7 is being adopted so quickly. I suspected that it would go down this way. Unfortunately the majority of package creators are still targeting PHP 5. Jordi has this to say on that.
As I wrote in the last update: I would like to encourage everyone to be a bit more aggressive in bumping PHP requirements when tagging new major releases of their libs. Don't forget that the old code does not go away, it's still there to be used by people using legacy PHP versions.
Read Jordi's blogpost here: https://seld.be/notes/php-versions-stats-2016-2-edition