Comment 9 for bug 1566520

My understanding is this RFE covers handling of data migration and contracted schema change by oslo.versionedobjects.

Before applying a contract migration, the DB schema is still an older version. N+1 version of neutron-server needs to be aware that an older version N of the schema is still used and needs to generate a new version of a versioned object (and also convert a data model to a new one [version N+1]). This needs to be done in the running neutron-server.
By doing so, N+1 version of neutron-server can work correctly even with N version of DB schema.

Is my understanding correct?