Which PHP versions are available to use trough the Boxfile?
The available php versions are listed here in this section of the Boxfile Guide http://help.pagodabox.com/customer/portal/articles/175475-understanding-the-boxfile#php-version.
Are you planning on supporting PHP 5.4 soon?
Yes. There are a couple of incompatibilities currently with some of the extensions, but once those are worked out we’ll announce the release in our blog.
5.4 is now available bit.ly/ZYKl1C