I'm not sure if you are trolling or have no idea how decimals and versioning work
(edit: on steam page it's v0.1.8 -> v0.2.0 -> v0.2.1. it's just written as decimal here, no biggie)
versioning doesn't necessarily must sequenced when released to public (in this case, public early access)
it just mean the dev already made v0.19 (not public), but decided to add more before release it, thus 0.2, the next iteration
0.1.8 to 0.2.0 makes sense
version numbers are different than regular decimals...
0.18 to 0.20 would also make sense
0.18.1 to 0.20.0 would also make sense
0.18.0 to 0.2.0 is a downgrade in version.
For instance, is it not fair to say, that for consistency sake, 0.2.0 came before 0.18.0?
However, if it's done on steam as 0.1.8 to 0.2.1... then that makes sense, as it's progressively going up.
Here on f95zone, to go from 0.18 to 0.2 is going down.
This is not a troll, this is just how numbers work. If it's a typo here, then so be it, it's a typo. If it's a version downgrade, it's a version downgrade, it wouldn't be the first game to go backwards.
However, based on what you said for the steam page, it's just a typo here.