From TS-212 to TS219 Migration was very easy. Though Qnap website said you would loose your mycloudnas name and several other settings, I got everything else migrated automatically.
It was as simple as swapping the hard drives from Old to new NAS and upgrading the firmware. Though the firmware couldn’t be downloaded onto NAS directly for some reason. I downloaded it on my PC first and them uploaded to NAS. Very easy Upgrade as you would expect.
Do other Qnap products also migrate this easily ? I hope so.