Welcome to the forum. Sorry for delay in answering. I haven’t used this keyboard in a while, and I just got a chance to test that my map still works in Ardour 9. It appears to be fine.
The general recipe is
Close Ardour
Put the midi map xml contents into a file in ~/.config/ardour9/midi_maps/akai_apc_key_25.map
(I think the midi_maps directory needs the underscore. And the file has to have a .map extension. The rest of the file name is arbitrary)
Start Ardour
edit > preferences > control surfaces >
double click generic midi
Incoming MIDI on: APC key 25 mk2 Control (In)
Outgoing MIDI on: Disconnected
MIDI Bindings: AKAI APC Key 25 mk2
That should be it.
You mention you have a slightly different version… is it the mk3 or something else?