The Discourse devs have made some updates to improve chat navigation and new functionality:
Access to chat threads (when you click the “reply” icon instead of just posting below a message, it makes a side-thread) these are more discoverable and have individual notification settings.
Private group chat upgrades
Adjustments to mobile interface
#2 is especially good because I know I had a group of people asking how to add more people to an existing private group chat, and to be able to give the group chat a name/title - these options didn’t exist and now you can accomplish both!