retroarchcustom.cfg and updates (yellow squares, extraction dir).Sound selection (ES must be restarted, not emulators).
sn2k: 8bitdo NES30 (default conf added to es_inputs.cfg), Sony DS4 (same), Sony DS3 (bluez5).
The install from a 4.0 or from a 4.1 will be automatic once released. Striked-through means there is still some development undergoing, so don't test yet. 4.1-stable is coming close, please test what you can and report your name, feel free to edit and add evolutions I missed.