PostgreSQL 11 Now Generally Available on Heroku Postgres
Change effective on 06 March 2019
PostgreSQL 11 is now generally available for Heroku Postgres. Newly provisioned databases will default to 11 - some hobby databases may still be created on 10.7 as we roll the fleet over the next few days. All pg:upgrade
commands will now upgrade databases to 11. Developers are encouraged to upgrade.