Upgrade from 2.8.3 to 2.8.4.
# UPGRADE URGENCY: MODERATE for Redis and Sentinel.
* [FIX] Makefile compatibility with non common make variants improved.
* [FIX] SDIFF crash in very unlikely to trigger state fixed.
* [FIX] Config rewriting fixed: don't wipe options unknown to the rewrite
* [FIX] Set TCP port to 0 works again to disable TCP networking.
* [FIX] Fixed replication with old Redis instances as masters by not
sending REPLCONF ACK to them.
* [FIX] Fix keyspace notifications rewrite and CONFIG GET output.
* [FIX] Fix RESTORE TTL handling in 32 bit systems (32 bit overflow).
* [NEW] Sentinel now has a run time configuration API.
* [NEW] Log when we lost connection with master or slave.
* [NEW] When instance is turned from slave to master now inherits the
old master replication offset when possible. This improves the
Sentinel failover procedure.
Update from 2.8.0-rc2 to 2.8.0-rc3.
Disable debug flags.
# UPGRADE URGENCY: HIGH
* [FIX] Improved expired keys collection algorithm. Even under heavy load keys
to be expired can't accumulate because of lack of CPU time.
* [FIX] Replication speed regression fixed (issue #1238).
* [FIX] Fixed an hard to trigger PSYNC bug.
* [FIX] Fixed Issue #1240, ZUNIONSTORE could lead to wrong result.
* [NEW] Add per-db average TTL information in INFO output.
* [NEW] redis-benchmark improvements.
* [NEW] dict.c API wrong usage detection.