1.4 About versions

The current stable version of Redis is 6. Many Linux distros still ship with version 5. Both talk protocol version 2. Version 6 also supports protocol version 3. The main differences are:

• The version 3 protocol has several improvements that notably improvement passing large objects using a streaming protocol.
• Hashes (maps) in the version 3 protocol are exchanged as lists of pairs (Name-Value), while version 2 exchanges hashes as a list of alternating names and values. This is visible to the user. High level predicates such as redis_get_hash/3 deal with both representations.
• The version 3 protocol supports push messages to deal with monitor and subscribe events on the same connection as used for handling normal requests.

New projects are encouraged to use Redis version 6 with the version 3 protocol. See redis_server/3.