The Rocket.Chat developers included support for Dolphin Pro authentication to the core package of Rocket.Chat, effectively making it possible for Dolphin users to update to newer version of Rocket.Chat without waiting for Chat+ integration update. More details in this pull discussion at GitHub.
This is not a full integration yet, but once the first step is made there's no going back. Good times! Thank you, Rocket.Chat team!
https://github.com/RocketChat/Rocket.Chat/releases