Backend Browser
See all the details here.
Frontend / Public Browsers
For the general public (and agencies / B2B channels), we support every major browsers that represent more than 1% of the usage on internet. As a reference, we use https://caniuse.com/usage-table
For example, let's look at IE, go down on the page and see which IE version represents more than 1% of usage (this screenshot is from 2020-02-07):
This means that IE 11 is supported (but 10 and before are not), Edge 18 (or later), then we've got Firefox 72, Chrome 79 and Safari 13.