It was released on the 23rd on Steam. It was already evening in Poland then, but GOG did update the Windows version on Christmas Eve, so hopefully the holidays will not delay the Mac and Linux versions too much.
The release was too late for press to pick up on any announcements, so there was just the Steam update news and a couple tweets. The last D:OS 2 Kickstarter update did say the Mac and Linux versions would be released any day.