UPBGE (Uchronia Project Blender Game Engine) is a fork of Blender created by Porteries Tristan (a Blender Game Engine developer) and some of his friends in September 2015.
It's an independent branch, and its aim is to clean up and improve current Blender Game Engine (BGE) code, experiment with new features, and implement forgotten features that currently exist but have not been merged with the official Blender trunk.
Currently, after the Blender Foundation's decision to delete BGE from next 2.8 release UPBGE becomes, de facto, the only one to follow the development of the Game Engine. This gives us even more freedom, if possible, to make certain decisions, since we will never, in any way, come into conflict with the official version.
Its development cycle spans the course of 4 months: 3 months to add new features and refactors and 1 months to fix bugs. Then a new release is made available for download (around 3 or 4 per year).
Regularly, the UPBGE merges the official Blender new patches, to stay up-to-date with the last Blender evolutions.
The UPBGE team is composed of volunteers; BGE users who are interested in the game engine development, a web developer, and a communication manager.
You can take a look at the release notes to see all the new features: UPBGE Release Notes
We hope that new users will join the project, to help us test new features, report bugs, provide feedback and ideas to improve UPBGE (https://github.com/UPBGE/blender/issues), and that new developers will join the team to help us develop shiny new features for the game engine.