With the C3 runtime, the only browsers not supported are IE and Safari 10 and older (Safari 11 being a grey area since it's partially supported, fully supported from Safari 12+). All other browsers can be assumed to work, because they auto-update.
The C2 runtime works with older browsers to the extent I think it would be hard to find something that doesn't support it these days. IIRC anything IE9+ will work. However the C2 runtime is considerably slower and has limited features.