If you would like to stop users from merging into an RC instance, or merging an RC instance into master (and tagging master) you can lock the instance.
Process for locking/unlocking an RC instance:
1. Go to the RC instance and open the SAK tools.
2. Under 'Actions' you will see 'Merge Lock'
The 'Merge Lock' job is only shown on RC instances.
3. Click 'lock' or 'unlock' on the job to change the merge lock status of the instance.
If you try to merge work into an RC instance, the locked branch won't be selectable in the target branch list and you will see the warning below:
When an RC instance is locked, the 'Author Release' button will be disabled, and the message below will be shown: