### Berkeley DB Reference Guide: Upgrading Berkeley DB Applications |

# Release 3.0: on-disk database format

Finally, you will need to upgrade your on-disk databases, as the Btree/Recno and Hash Access Method database formats changed in the Berkeley DB 3.0 release. (The on-disk Btree/Recno format changed from version 6 to version 7. The on-disk Hash format changed from version 5 to version 6.)

Until the underlying databases are upgraded, the DB->open function will return a DB_OLD_VERSION error.

For further information on upgrading database formats, see "Upgrading databases".

Copyright Sleepycat Software