It supposedly supports RS3 but I can't figure out how to make it work. It only detects the "oldschool" clients and doesn't appear to have any mechanism for detecting the RS3 client (I opened the application in a debugger -- it doesn't even look for the RS3 client).
RS3 is no longer programmed in Java which also means it is no longer supported by any botting community - unless you pay for private scripts bots which is built differently and you will probably pay a T O N for. RS3 is now NXT which is when it was no longer supported.
