[2019] Is Co-op finally coming in the December update ?

Hello slackpanda,

Welcome to the forums! Yes, that is correct. As you can see from our Anno Union blog below:

Game Update 6, including the previously announced co-op mode and statistics system, will be released alongside our third DLC, The Passage, in December. Combining all these content drops into one update will allow us to focus all of our polishing efforts into one release, giving us extra time for additional extensive testing of all the new content and new features.

I'd recommend keeping an eye on the blog for all of our latest updates.

Originally Posted by cuttyhunker
Watching Anno Union video will explain coop well. Looks very interesting as I have never played a game with coop before.

It is quite fun. I hope that you enjoy it with some friends when the update drops!