Redis 4.0 EOL

[perzarys]

Description

Redis 4.0 is deprecated (image last pushed to docker hub in 2020), however it's still used in the compose yaml. It would be good to make a switch to a more recent and maintained. Azure switched to Redis 6 for instances having used Redis 4 before.

[luckydonald]

Probably switching to Valkey (Truly open-source fork, maintained by the Linux Foundation) instead would be a good way forward.