OpenUpgrade Framework is a technical module that contains a number
of monkeypatches to improve the behaviour of Odoo when migrating
your database using the OpenUpgrade migration scripts:

- Prevent dropping columns or tables in the database when fields
  or models are obsoleted in the Odoo data model of the target release.
- When data records are deleted during the migration (such as views or
  other system records), this is done in a secure mode. If the deletion
  fails because of some unforeseen dependency, the deletion will be
  cancelled and a message is logged, after which the migration continues.
- Prevent a number of log messages that do not apply when using OpenUpgrade.
- Suppress log messages about failed view validation, which are to be expected
  during a migration.
- Run migration scripts for modules that are installed as new dependencies of
  upgraded modules (when there are such scripts for those particular modules)
- Production databases generated with demo data, will be transformed to
  non-demo ones. If you want to avoid that, you have to pass through the
  environment variable OPENUPGRADE_USE_DEMO, the value "yes".