---
prelude: >
  - Database downgrades have been removed from the Glance
    source tree.
upgrade:
  - The ``db_downgrade`` command has been removed from the
    ``glance-manage`` utility and all database downgrade
    scripts have been removed.  In accord with OpenStack
    policy, Glance cannot be downgraded any more.  Operators
    are advised to make a full database backup of their
    production data before attempting any upgrade.