Hi there!
I am a french native with a master degree in web developement.
I am currently working with a German, a Spanish and 2 Chinese companies as their webmaster and web developer.
I can test all the features of your app from Windows 10, all the way down to Windows 7.
You'll get a document feedback on every aspect of it with recommandations, suggestions, problem descriptions, screenshots and videos.
Looking forward to hearing from you.
Best regards,
Yassine.