Translations:PostgreSQL/QuickStart/83/en

However, there are two caveats with using pg_upgrade. Firstly, it does not support configuration files being in a different directory than where the data is stored. This can be resolved by using symbolic links. Lastly, you can only use it to migrate from a database from 8.3 or newer. If you have an older database you will need to follow the instructions to migrate from pre-9.0 deployments.