Database Migration Service supports continuous migrations from PostgreSQL source
databases to AlloyDB for PostgreSQL destination clusters.

## Supported sources

Database Migration Service supports continuous migrations from the following source
databases and versions:

- Amazon RDS 9.6.10+, 10.5+, 11.1+, 12, 13, 14, 15, 16, 17, 18
- Amazon Aurora 10.11+, 11.6+, 12.4+, 13.3+, 14, 15, 16, 17, 18
- Self-managed PostgreSQL (on premises or on any cloud VM that you fully control) 9.4, 9.5, 9.6, 10, 11, 12, 13, 14, 15, 16, 17, 18
- Cloud SQL 9.6, 10, 11, 12, 13, 14, 15, 16, 17, 18

For all supported source database offerings, Database Migration Service can migrate
the databases you select from your source server.
Certain system schemas and tables can't be migrated. For more information, see
[Known limitations](https://docs.cloud.google.com/database-migration/docs/postgresql-to-alloydb/known-limitations.md.txt).

## Supported destinations

Database Migration Service supports migrations to destination AlloyDB for PostgreSQL clusters
running the following major versions:

- AlloyDB for PostgreSQL 14, 15, 16, 17, 18

The destination is an AlloyDB for PostgreSQL cluster consisting of a primary instance
and optional read pool instances that provide high availability and read scale.

## Cross-version support

Database Migration Service supports migrating from any supported source PostgreSQL
version to the same or a later major version on AlloyDB for PostgreSQL:

- **Standard migrations**: Migrating from a later major version to an earlier major version (for example, from PostgreSQL 16 to 15) is unsupported. Migrating from a later minor version to an earlier minor version isn't recommended.
- **Quick-start migrations**: Migrating to an earlier major version is permitted. Database Migration Service displays a warning rather than blocking the operation.

## What's next

- For more information on feature support and constraints, see
  [Known limitations](https://docs.cloud.google.com/database-migration/docs/postgresql-to-alloydb/known-limitations.md.txt).

- To review the end-to-end migration process, see the
  [Scenario overview](https://docs.cloud.google.com/database-migration/docs/postgresql-to-alloydb/scenario-overview.md.txt).

- To get started with a migration walkthrough, see
  [Get started with AlloyDB for PostgreSQL migrations](https://docs.cloud.google.com/database-migration/docs/postgresql-to-alloydb/get-started-with-alloydb-migrations.md.txt).