no one knows what the Air 2S is going to be, or features it will have... if it was a major upgrade, surely it would be called Air 3.
given regulation changes (particularly here in EU, and the C ratings), Id not be surprised if its to bring in line with regulations.
these kind of things, are possibly 'necessary', but would not warrant a version number increment.
they could also move it over to using O3, but why do this with the Air only... you'd perhaps expect this to be done on the Mavic Pro?
but its all mere speculation, given all we have seen leaked is the filing with a new name
as for buying, DJI I think are fast for shipping main unit... just becareful on things like fly more pack... which here in the EU, they dont seem to have, yet some retailers do have.
(of course, you could buy the main pack from DJI, and source fly more pack elsewhere, which Im kind of wishing I had done !)