Looks like the wait is over.

http://blog.waifubartending.com/post/154613222473/formally-announcing-prologue-redux-most-of-you

Yes its gonna be a free update,yes GoG too. :)

Heck yes more cyberpunk bartending, glad the devs didn't forget about us GOG buyers as so many tend to do.
Already played the prologue and the special demo but this is a perfect excuse to play the whole thing again.