# 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.

If you perform a soft upgrade, you will not be able to perform certain functions that are not available in older versions of Derby. For example, the following Derby Version 10.2 features cannot be used in a database that has been soft upgraded from 10.0:

- SYNONYMS
- Creating tables using the GENERATED BY DEFAULT option for identity columns
- Reclaiming unused space using the SYSCS_UTIL.SYSCS_INPLACE_COMPRESS_TABLE procedure

The following 10.2 features cannot be accessed from a database which has been soft upgraded from 10.1:

- GRANT/REVOKE
- Online backup procedures SYSCS_UTIL.SYSCS_BACKUP_DATABASE_NOWAIT and SYSCS_UTIL.SYSCS_BACKUP_DATABASE_AND_ENABLE_LOG_ARCHIVE_MODE_NOWAIT.
- The encryption or re-encryption of a database with a new phrase/key.

Other new features in Derby that do not affect database structure, such as using timestamp arithmetic, are allowed in a soft upgraded database.

To perform a soft upgrade on a database created using an earlier version of Derby:

Simply connect to the database, as shown in the following example:

    connect 'jdbc:derby:sample'

In this example, the sample database is a Version 10.0 database.
Parent topic: Upgrades
Related tasks
Preparing to upgrade
Upgrading a database