Issue
pg:upgrade functionality is changing with the introduction of new Postgres version upgrade subcommands
Resolution
We're changing the functionality in the pg:upgrade CLI command for upgrading Postgres versions on Heroku Postgres. You can still use the command until it reaches end-of-life on May 21, 2026. We recommend using the new pg:upgrade:* subcommands or pg:copy to upgrade the Postgres version on your database.
See Upgrading the Version of a Heroku Postgres Database for version upgrade instructions.