I'm an Ubuntu user myself, I upgraded using the above method and it worked out very well.
I'm running Mint 18.3 now dual boot with Win 10 (although at this time I couldn't care less about Win 10; I wouldn't mind repartitioning and removing WIN 10 completely). I would like to see a set of instructions to remove the Win 10 partition(s) and go completely to Mint 19. That's an oddball configuration (I think), and I'm not geeky enough to do it myself without a step by step set of instructions.