I am on kernel 4.20.0 on my mio 4k, so is safe to upgrade to TNAP V.2?
If so I can't wait to see the new software release!
Technically, there is no TNAP 2.0 as of yet for the slightly older Mio 4k that we all have. This one is specifically for the new Mio+.
It will run on our older Mio's, BUT, you won't have anything showing on the front panel LED screen. That's because the Mio+ doesn't use the same display. Also, for the Hauppage ATSC tuners, I believe it only works on the 955q so far (which I have). I have a copy of it from El Bandido that I'm testing now. As time permits, he is going to make a new firmware for our older Mio's.
Oh, and YES, you can have firmware's with different kernels in different slots, with no interference between them.