I've put an order in on a new Wahoo Kickr v5 (2020) which I got on a good sale. I've bought a relatively inexpensive road bike (also on sale) to be (more or less) permanently mounted on the Kickr. The road bike, since it's inexpensive, only has 8 speeds on the cassette. I know the Kickr comes with a Shimano 11-speed cassette already installed.
I was told by the bike store that the 11-speed cassette won't work with the bike I bought, and that I need to install an 8-speed cassette. They said this will work fine (although of course it won't provide as fine a gradation of gear changes as the 11 speed). I just wanted to check that that was true -- that is, are there any issues I should be aware of when using the Kickr with an 8-speed cassette? Like calibration, or that the apps work correctly with the 8-speed cassette and 8-speed bike? I was wondering whether, having come with an 11-speed cassette, it was in some way "programmed" or "calibrated" for that cassette.
This is my first training wheel, and I'm ignorant of exactly how it works. Is all that the Kickr cares about how fast the axle is turning? That is, the bike is another world it doesn't care about, so you can use any cassette without concern?