5.0 is the newest version the original Japanese version can be found on @fallboy3656622’s pixiv.
There is also a machine translation provided by @humblesasquatch.
Also of note a mod is being worked on that fully translates the game to English as well as continues/expands upon a mod that was made by @Kitsune. Which changed the main character to female, update their sprite in 4.0, and added a robust translation among many other changes.