Our plugin uses the FileMaker 7 plugin format. So until FileMaker 6 the way of writing plugins was different and changed for version 7. When I started writing a FileMaker plugin, the version 8 was current and so I started there and quickly made sure my plugin works on 7 and 8. Over the years we continue with the same interface to FileMaker. All newer functions are weak linked, so our plugin loads in older versions.
For Mac you can use FileMaker 8.5 (Released 2006) to current one. That is due to the switch to Intel CPUs by Apple in 2006 and 8.5 was the first version to support x86 CPUs. We later dropped PPC support and you still can get a copy of our plugin in version 2.4 for PPC support. Current plugin requires Mac OS X 10.6 and newer.
With Windows you can even go back to FileMaker 7 if you like, 12 years back! Current plugin works fine there as well as with newer versions of FileMaker. The picture above shows FileMaker 8 on Windows 10 (Server 2016) with current MBS Plugin from earlier today. We support Windows XP and newer.
If you are lucky to be a member of FileMaker's beta testing, you an even try our plugin with the next FileMaker version and find some new features.
Finally please keep your plugin installation up to date to benefit from bug fixes and improved features. Don't waste hours figuring out details about a bug in an ancient plugin version, which has been fixed last year.