Feature freeze
From MythTV Official Wiki
A feature freeze is a revision-control policy that states that no more feature patches will be accepted into a given branch of a software package's repository. They are usually declared prepatory to a new release, so that all the Last Bugs can be worked out before a wider release -- users are commonly encouraged to download and test the package to find these.
Bug fix patches are usually accepted during a feature freeze; it depends on how frozen the code actually is...