phpReunion has been tested on Apache 2.0.46, with PHP 4.3.2 and MySQL 3.2.54 all running on windows XP home, although it should work with PHP versions at least 4.1.0 and any OS/Apache combination.

If you find an incompatability, let me know, and I will add it here/try to fix it.
Also, if you find it works with your setup, please let me know so that I can add it my list of compatible versions.