Command: heroku pgbackups:capture --remote production
Response: >>> HEROKU_POSTGRESQL_COLOR_URL (DATABASE_URL) ----backup---> a712
Command: heroku pgbackups:url [db_key] --remote production
Prepare your RDS instance and [authorize access to it][1] (basically make it public).
Put your app in maintenance mode:
heroku maintenance:on
Save the latest SQL dump of the DB:
TL;DR
Install Postgres 9.6, and then:
sudo pg_dropcluster 9.6 main --stop
sudo pg_upgradecluster 9.5 main
sudo pg_dropcluster 9.5 main