Xbox Insiders are currently testing out some new Discord functionality on the Xbox Series X|S and Xbox One. New features for Discord on Xbox include better integration between Discord activity and Xbox friends, direct call functionality, and the ability to watch Discord streams directly through their console.
Making direct calls within Discord will be available to Xbox users. This means you will not have to join a vacant voice channel if you want to talk to just one other person. The integration with Xbox friends also now means you can see who's chatting or using Discord within your Xbox Friends list under the "Happening Now" section. Watching Discord streams is also a highly requested feature and with this update, you will be able to watch streams from friends without issue.
These new features are currently being tested for those enrolled in the Xbox Insiders program. There is no set release date on when the testing will end and the update will be rolled out to everyone globally.
