Currently, when releases a major branch that is out-of-support, the release tool's action is to make a normal minor release. The tool has the information required to detect that the branch is out-of-support, though, and could perform the extra steps required in that situation. Namely:
Send a special email entitled [OutOfSupport] repo vY.x.x.
Change the repo's default branch.
Delete the out-of-support major branch and all minor branches for the same major.
(Update the list of supported branches in the repo's README.)
Currently, when releases a major branch that is out-of-support, the release tool's action is to make a normal minor release. The tool has the information required to detect that the branch is out-of-support, though, and could perform the extra steps required in that situation. Namely:
[OutOfSupport] repo vY.x.x
.