Issue
I would like to use Redis Notification feature, but I get an error message "(error) ERR unknown command 'config'".
Resolution
Heroku Redis doesn't currently support keyspace notifications. In some cases, similar results can be achieved via the SUBSCRIBE and PSUBSCRIBE methods which we do support.
In the event that we do add support for this in future, you can be notified by subscribing to the Heroku Changelog if you aren't already. This will let you know about updates, improvements and deprecations ahead of time so that you can make any necessary adjustments.