Blizzard is internally testing at least two content updates for the game (Patch 1.1 and 1.2), according to build numbers from the various dev branches on the CDN.

The codename for Diablo 4 is fenris and there are multiple instances/dev branches up and running on different builds, as you can see below.

Diablo IV Vendor (fenrisvendor) is currently running on Patch 1.1.x.42477. This build is encrypted. We believe Patch 1.1 will be the first major content update for Diablo 4.

Diablo IV Vendor 2 (fenrisvendor2) is running on 0.0.1 Build 42203. This build is encrypted.

Dablo IV Vendor 3 (fenrisvendor3) is running on 1.2.x.42428. This build is also encrypted.

Screenshot courtesy of diablo4.cc