Android Wear 2.0 was officially released in February, but many watches are still waiting on an official update. The ZenWatch 2 and 3 were confirmed to get the new version (the original ZenWatch was left out), but last we heard, it would come sometime in Q2 2017. Now the rollout seems to be in full swing, at least for the ZenWatch 3.
The official Twitter account for ASUS in the United Kingdom tweeted this earlier today:
I was unable to find photos of the update running on the ZW3 anywhere on social media, so I doubt this has actually been pushed to many watches yet. Let us know in the comments if you have it on your ZW3 yet.