# Upgrades

To connect to a database created with a previous version of Derby, you must first upgrade that database.

Upgrading involves writing changes to the system tables, so it is not possible for databases on read-only media. The upgrade process:

- marks the database as upgraded to the current release (Version 10.4).
- allows use of new features.

See the release notes for more information on upgrading your databases to this version of Derby.

- Preparing to upgrade
  Upgrading your database occurs the first time the new Derby software connects to the old database.
- Upgrading a database
  To upgrade a database, you must explicitly request an upgrade the first time you connect to the database with the new version of Derby.
- Soft upgrade limitations
  Soft upgrade allows you to run a newer version of Derby against an existing database without having to fully upgrade the database. This means that you can continue to run an older version of Derby against the database.