nope. AFAIK the people that were in charge of that product fell off the face of the earth sometime in 2013, and I've been hearing continual stories of it bricking or failing ever since. Their latest version stated it was FMS13 compatible, but from what I've heard there are issues still going back to FMS13.
Your best option for longevity is to update to the filemaker PHP API and rewrite sections in native PHP as appropriate. with ~3k logins per week, it seems like it's mission critical enough that you can make the investment. Might be a good time to get a mentor that knows the PHP API to pitch in.
Thanks for the reply Mike. Much appreciated.
I did get a response from FMWebSchool (see Allyson's email message at bottom) that helped us band-aid (sticky plaster) the situation. The PHP API installed with FileMaker Server 12 and downgrading to PHP 4 enabled us to limp onwards in this instance. Catastrophe narrowly averted, I will now look at re-writing the web sites using native FM PHP API commands, as you suggested.
Although, this pressure situation did force me to experiment with WebDirect for the first time ever as a possible "Plan B". I was able to re-build the core modules of the web sites within a day. Single user performance was phenomenal, just need to test the performance under load with lots of users.
FMStudio Pro has only been fully tested and supported through FMS13. Was
your site created with FMStudio Pro? If so, you would need to use the API
files that were provided for FMS12.