It's HERE!

According to Galaxy, it was added FOUR HOURS AGO?!

But I only just noticed it come up just then, so I'm guessing it actually released about 15 minutes ago... which I believe is right on time (?). So well done GOG.

So how do those of us who have bought it before get it?

Check for updates

On Steam, it's available as a patch for those who already own the game. Maybe it's the same thing here?

No Update in Galaxy but on the website I was able to download the offline installer for the Final Cut (at least it's called that way). Turns out, it's still the old version. ¯\_(ツ)_/¯
GOG at it's best again...

Since few minutes I'm downloading update (~17GB) through Galaxy. Try restarting.

Starting & exiting the game did start the download for me.

I take everything back! You're right. The update is installing right now. :-)

Weeeeeh, installing it now. So happy it is finally here! Huge thank you to the devs, this will make my Easter holidays soooo much better!

I just bought the game and I don't want to use Galaxy on my MacBook. The Mac installer is still the old installer unfortunately.

Is there any easy way to tell if the game is successfully updated (like a splash screen or something)?
I had the game installed before the patch and I haven't noticed it update but when I check for updates nothing happens.
And yes have opened and restarted both the game and Galaxy.

Start a new game. If you get voice over in the english version you got the update.

Well there was always voice over in the intro.

Easiest way to check is to go to your options screen - if you've updated successfully, there should be a new option for voice, where you can choose from "Classic", "Psychological", or "All". If you have that option, you're set.
I know this is coming too late since you've no doubt figured it out by now and already have it - but I already owned the original, I just checked Galaxy and there was a new update.

And amazingly enough, I then checked the Games section on the website (i.e. without Galaxy), and the new update was there. Not really possible to miss, it was pretty obviously labelled.

Obvious as it may be, it was also wrong (at least for Macs). It was called "The Final Cut" but it was still the old file. They've finally updated, however. The 17.5GB file is the new version.

My bad yeah there always was a voice over in the intro. The check option, than is indeed the fastest way to check for the update.