It seem to be that the newest public version is 0.19.f on their patreon from the date of May 6, 2021. Here:
https://www.patreon.com/posts/0-19-e-release-0-50933389
So even if the game is not abandoned, the developer must have forgotten about updating the itch version. It would be sad if it was abandoned. The game looks very interesting from the screenshots.