I have contacted the developers of this visual novel, and they said they admitted the both the update and the expansion pack to GOG a long time ago.

However - When I check the download it's still on version number 1.00 (original release), and the expansion pack "Highway Blossoms Next Exit" is nowhere to be seen. That's a shame, because it's already released more than a month ago and I would like to buy it.

Has something gone wrong? Has it something to do with the developers, or is GOG just terrible lazy? What the hell is going on?

Is there anyone who knows more about this?

Have you contacted GOG support?

The new version makes some changes to the original. If you like the original, I recommend backing it up before getting the Next Exit version (if it releases here).

https://steamcommunity.com/app/451760/discussions/0/2841165820091483974/

Windows, Galaxy only for now:
Update to 2.5.4 (2020-11-18)
Highway Blossoms: Next Exit released 2020-11-20


EDIT
all updated now:
Win+Mac, Galaxy and offline installers: version 2.5.4
Linux: version 2.5.41

Thanks for the heads-up! Bought.