I am on a Mac.  The checkout button in the Control app just brings me to a page asking me to upgrade my browser to a TLS 1.2 version.  If Internet Explorer is the app's browser, how can I get around this issue on Mac?  I do not have an iOS device to try it on either.

Internet Explorer is the app's browser on Windows but not on Mac; on Mac it uses Safari.  What version of macOS are you using?

We also support buying algorithms on Android devices if that helps.