Change effective on 17 October 2019
Redis 5.0 is now the default version for all new Heroku Redis instances.
This version is backward compatible with Redis 4.0 and introduces several new features:
ZPOPMIN/MAXoperations on sorted sets (with blocking variants).
The HELPsubcommands was added for many existing commands.
For more information on version support and legacy infrastructure, please see the Heroku Redis documentation.