Hi everyone,
Blender development is split into various release phases which were called Bcon.
Even though this was a fun naming scheme (inspired by the United States Defcon state, with flipped numbering though 
) it was time to move to a more conventional naming scheme, making things clearer to contributors and developers, especially for people who are new to Blender.
You can find all information on the new naming and what is allowed in which phase in the developer docs.
In short:
Bcon1 and Bcon2 have been merged into one phase, called Alpha
Bcon3 → Beta
Bcon4 → Release Candidate
Bcon5 → Release
Risky changes that are likely to cause bugs or additional work must be done within the first few weeks of the Alpha phase. Afterwards only smaller and less risky changes, including small features, should be made. Once we enter the Beta phase, only bug fixes are allowed.
