There is a bit of confusion in the UI between required and supported. The Moodle versions supported can be either one or many, but for PHP, there is no chance of a plugin working for an earlier version of PHP and not for a later one. This leads to a bit of confusion on the versions download tab, where we end up with a requirement for multiple PHP versions, rather than a minimum.

I'd suggest separating the PHP and Moodle bits, so that Moodle is 'supported versions' and PHP is a 'minimum requirement', chosen by the developer using a dropdown.