Hi buttonpro19 ! Thank you for your feedback and your browser tests!
About IE (Internet Explorer)
We're not sure if we want to support Internet Explorer as it's an old browser that does not support many modern scripting languages. Also, Microsofts employees are advicing companies to not use the browser anymore (source: Microsoft tech community ). But we may look for an work around for this, but to be honest, I am not sure if that is worth it. Internet Explorer isn't that big anymore as it used to be in the past.
Do you have customers who are still using Internet Explorer on your website? You may check this on Google Analytics (or any other analytics, if you have that available). we'd love to hear that!
The other browsers
About the rest of the browsers, Buttonizer should work and we'll make sure that it works. What versions of these browsers did you test? We'll do the same tests and make sure it will work 🙂