Is Redis v3.2.x backwards compatible with v2.8.x?

Question

I am attempting to upgrade from Redis 2.8 to 3.2. All functionality seems to remain intact in my application, but I am left wondering

• If there are a set of non-backwards compatible changes I need to take care of?
• If my data generated and persisted to disk in Redis 2.8 will work properly with the 3.2 server?

Answer 1

Release notes are on github https://github.com/antirez/redis

Here's a snippet from the release notes for v3.0 and v.3.2

Migrating from 2.8 to 3.0 =========================

Redis 2.8 is mostly a strict subset of 3.0, you should not have any problem upgrading your application from 2.8 to 3.0. However this is a list of small non-backward compatible changes introduced in the 3.0 release:

• The log format was modified. The prefix of each line included the pid in the following format [1234]. Now instead it is 1234:? Where '?' is actually the role of the instance. M for master, S for slave, C if this process is a saving child (for RDB/AOF), and X for Sentinel.

• The default maxmemory policy in Redis 3.0 is no longer "volatile-lru" as it used to be in 2.8, but "noeviction". The policies behavior is the same (but LRU eviction is much more precise in 3.0), so only the default value changed. Just make sure to specify in your redis.conf what you mean.

https://raw.githubusercontent.com/antirez/redis/3.0/00-RELEASENOTES

Migrating from 3.0 to 3.2

Redis 3.0 is mostly a strict subset of 3.2, you should not have any problem upgrading your application from 3.0 to 3.2. However this is a list of small non-backward compatible changes introduced in the 3.2 release:

• The default configuration file now binds to 127.0.0.1.
• Slaves try to no longer expose stale data about already expired keys.
• The RDB format changed. Redis 3.2 is still able to read 3.0 (and all the past versions) files, but not the other way around.
• Behavior on crash may be different. The crash log format changed and the memory test executed is now different.

https://raw.githubusercontent.com/antirez/redis/3.2/00-RELEASENOTES