Amazing game, but I'm a bit confused by version numbering and release dates. The first messages are from 2019 and there were versions like 0.6-0.8, what's the history here?
There's a pretty standard approach to version numbers where the version number is split into separate sections by periods, with the number in each section being any integer, rather than the entire version number being a decimal number.
For this game, the version number starts with 0 to indicate the game isn't complete yet, then the next number (now up to 16) tracking significant content additions and code/engine changes, then the third number is separate planned releases (sometimes with new content) and the fourth number is for buxfixes and patches.
So 0.16.1 was the first planned release of v16 of the in-development game, followed by 0.16.2 and 0.16.3, the public release of v16, which was followed by bugfix patches 0.16.3.1, 0.16.3.2 and 0.16.3.3. 0.16.4 breaks the pattern, as an additional release for v16, adding some extra content, but not enough to label it v17, and was then followed by three patches - 0.16.4.1, 0.16.4.2 and 0.16.4.3 - making bugfixes to 0.16.4.