I was using version 4.0.1, although I now see that version 4.3.0 is available. From what I can tell, the difference seems to be very minor, so it shouldn’t matter. You will need a copy of the Kickstart ROM and Workbench disk images, version 3.0 or 3.1. This is still under copyright, and at least the Workbench images can be bought from. They can also be found on several places on the Internet, as usual DuckDuckGo is your friend.
You probably want to use the PFS3 file system, and you will need to download the handler for that from.