Is there a way to restrict the choices available on the CR field to those builds currently supported or actively under development?
Unfortunately, there is no way via the client or server to filter label selection. However, labels are listed in a chronological order from the dropdown menu so the latest build labels are always available from the top of the list.
The option of archiving labels also isn’t possible as the reference to the view in which it is created as well as any attached CR’s would also need to be archived.
Label deletion detaches the label from its view/CR and removes it from the database. The view/CR remains unaffected.