The PostgreSQL database is constantly evolving. As a PostgreSQL administrator, you will occasionally need to upgrade an existing database to a new release. Fortunately, upgrading an existing database is usually a simple process.
In most cases, the only work required to move to a new release is to dump the entire database cluster (using pg_dumpall), install the new software, and restore from the dump. Installing a new release this way is nearly identical to performing a backup and restore operation. For some upgrade paths, you don't even need to dump/restore?the new release includes a pg_upgrade utility that upgrades your data in place.