Allow administrators to "freeze" a revision on the roadmap
Currently we keep all our revisions on our roadmap for auditing purposes. We have several non technical users that submit feature requests via Redmine, and have a large list of versions in our roadmap. Even though many of these versions have been long since released, they still appear as an option when filing a new issue. This causes a mangment nightmare. It would be nice if we could "freeze" a version and not allow users to assign any more issues to it. This would also be useful for stopping new features added on to a version shortly before it's release.