Don't get stuck on crap old versions of PHP just because your host does not support it. Keep using the newest version, and if you gotta switch... maybe you gotta switch.
Curious to know the history of the project and where we hope to take it?
Check out this article from HostingAdvice.com!Sure why not! Shout at @matthewtrask or @colinodell on Twitter, or send a pull request to the GitHub repo.
This used to be entirely manual, which was a horrendous to keep up to date. Now we parse phpinfo() on public URLs that hosts make available, like this:
http://php70.webhosting.be/phpinfo.php
Not all hosts have them so some are still entirely manual. Either way, sending us patch version changes, changes in the default versions, or new public phpinfo URLs can be done via updating hosts.yml.
Read the contributing guide on GitHub.
I have a bit of a todo list, and I would love help if you're bored.