5 - Cluster and Ring pipelines process commands for each node in its own goroutine.
9 - Added Options.MinIdleConns.
10 - Added Options.MaxConnAge.
11 - PoolStats.FreeConns is renamed to PoolStats.IdleConns.
12 - Add Client.Do to simplify creating custom commands.
13 - Add Cmd.String, Cmd.Int, Cmd.Int64, Cmd.Uint64, Cmd.Float64, and Cmd.Bool helpers.
18 - Ring got new options called `HashReplicas` and `Hash`. It is recommended to set `HashReplicas = 1000` for better keys distribution between shards.
19 - Cluster client was optimized to use much less memory when reloading cluster state.
20 - PubSub.ReceiveMessage is re-worked to not use ReceiveTimeout so it does not lose data when timeout occurres. In most cases it is recommended to use PubSub.Channel instead.
21 - Dialer.KeepAlive is set to 5 minutes by default.
25 - ClusterClient got new option called `ClusterSlots` which allows to build cluster of normal Redis Servers that don't have cluster mode enabled. See https://godoc.org/github.com/go-redis/redis#example-NewClusterClient--ManualSetup