In a nutshell
VID can be upgraded in-place (remove and replace), or in a blue/green strategy.
Its database schema are upgraded as needed, if needed. No data migration is needed.
It is possible that in some cases VID cannot be rolled-back after a database schema upgrade; i.e. the schema might not be backward-compatible.
These cases are rare, and development team is doing efforts to identify these cases, and minimize those.
If such case happen, the simplest solution is to drop the database schema, and let VID recreate it from scratch.
Supporting Facts
VID is mostly a stateless component. Any needed information is retrieved on runtime through third-party API.
VID does not store any unrecoverable information.
Thus, a fresh installation of VID works the same as a tenure deployment.
To manage database schemas, VID automatically use a designated tool (Liquibase).
References:
Frankfurt Code Impact View per Component
VID-702 - Getting issue details... STATUS