On dedicated plans you have full control over which version of PostgreSQL you want to run. To upgrade to a more recent version, go to the ElephantSQL control panel select the instance you want to upgrade and go the Admin tab. There you can select the version you want to upgrade to.
The upgrade process will take a few minutes up to an hour depending on the size of the database. We always start by taking a fresh backup of the entire server so that we can roll back in case of any issues.
It's important to note that there can be breaking changes between versions of PostgreSQL. You can read about them in the PostgreSQL release notes . You should also try to run your application against the new version before upgrading your production database.
Depending on the version you are upgrading from, and what version the underlying operating system is running, you may need to upgrade in steps as some combinations of PostgreSQL version, OS version and PostgreSQL extension versions are not possible. You will be notified in the control panel if this is the case. The plv8 extension is no longer packaged and will be disabled automatically when upgrading.