Need Beta Testers With Macs

I've putting the finishing touches on a little Java app that straightens and crops stamp scans, and I need some last minute help.

I think I've got a good, solid version running on Windows and Mac (sorry Linux crowd, not yet).

However, I need to do some additional testing to determine exactly which versions of OSX it will run on. The software that does the graphics processing in the app relies on functions within OSX that aren't present in older versions of the OS. I suspect the change came between 10.8 (Mountain Lion) and 10.9 (Mavericks), but I'm not sure.

It's theoretically possible to fix it, but before I go down that road, I'd like to see exactly how big the problem is. I know it doesn't run on 10.7 (Lion), and it does run on 10.11 (El Capitan). If anyone has 10.8 (Mountain Lion), 10.9 (Mavericks) or 10.10 (Yosemite) and is willing to do some quick testing please let me know.

I could also use someone else to do a quick test of 10.11 (El Capitan), as the only 10.11 system I've tested on is my own. Because I wrote the software on my 10.11 computer, there's software installed that the average end-user won't have, and I need to make sure it will work on a "clean" computer.

Thanks in advance.