It seems Aspyr Media hit a small roadblock when trying to get the latest Civilization VI patch out for Linux, the one to finally give cross-platform online support.
Back near the start of August, we reported that Aspyr Media had put the patch forward to their partners to get it approved and put live on Steam. An hour ago, Aspyr-Blair commented on the Steam forum about the delay with it still not being released yet:
I've been at Gamescom since last Friday, so apologies for the delay in response. A crash bug was found on a specific chipset during final test/approval. We are fixing now, and hope to get the build back into approvals this week.
It has been a long wait, with the cross-platform patch originally due back around mid-April 2017. Honestly, I forgot all about it again because of the delay. That's what happens though, if something gets delayed again and again people do forget and move on.
Hopefully, it means the publisher only needs to re-confirm that specific issue is fixed. Otherwise, we might be in for another pause.