Using 3.0 but have to upgrade from 1X?

I'm a bit confused about all of this.. I am using clip studio paint 3.0.4 version but if I wanted to upgrade to 4.0 I think I have to buy the upgrade to 2.0 first then 3.0 then 4.0?
I don't have a good memory so I don't know how I got 3.0.
Does it even make sense to upgrade from 1.0 X to 4.0 X or do I just buy the 4.0 X instead idk?
I did read a few posts but I'm still confused and some people mentioned the worry of losing something after upgrades?
(I'm using the windows version)