Redis Open Source 8.6 release notes

Redis Open Source 8.6 release notes.

Redis Open Source 8.6-RC1 (January 2026)

This is the first Release Candidate of Redis 8.6 in Redis Open Source.

Release Candidates are feature-complete pre-releases. Pre-releases are not suitable for production use.

#14615 Streams: XADD idempotency (at-most-once guarantee) with new IDMPAUTO and IDMP arguments.
#14624 New eviction policies - least recently modified: volatile-lrm and allkeys-lrm.
#14680 Hot keys detection and reporting; new command: HOTKEYS.
#14610 TLS certificate-based automatic client authentication.
RedisTimeSeries/RedisTimeSeries#1853 Time series: support NaN values; new aggregators: COUNTNAN and COUNTALL.

#14645 Hide personally identifiable information from ACL log.
#14659 ACL: Key-pattern bypass in MSETEX.
RedisTimeSeries/RedisTimeSeries#1837, RedisJSON/RedisJSON#1474 Hide personally identifiable information from server log.
RedisBloom/RedisBloom#950 Out-of-bounds read when loading an invalid RDB file (MOD-12802).

#14545 ACL: AOF loading fails if ACL rules are changed and don't allow some commands in MULTI-EXEC.
#14637 Atomic slot migration: wrong adjacent slot range behavior.
#14567 Atomic slot migration: support delay trimming slots after finishing migrating slots.
#14623 Streams: XTRIM/XADD with approx mode (~) don’t delete entries for DELREF/ACKED strategies.
#14552 Streams: Incorrect behavior when using XDELEX...ACKED after XGROUP DESTROY.
#14537 SCAN: restore original filter order (revert change introduced in 8.2).
#14581 Rare server hang at shutdown.
#14597 Panic when cluster node is uninitialized.
#14583 FLUSHALL ASYNC on a writable replica may block the main thread for an extended period.
#14504 Cluster: fix race condition in broadcast configuration.
#14416 Fixed argument position handling in Redis APIs.
RedisTimeSeries/RedisTimeSeries#1784, RedisTimeSeries/RedisTimeSeries#1839, RedisBloom/RedisBloom#952, RedisJSON/RedisJSON#1477 Atomic slot migration support.
RedisBloom/RedisBloom#946 MEMORY USAGE: fix reported value (MOD-12799).
RedisJSON/RedisJSON#1473 Adding escapes to already-escaped characters (MOD-8137).
RedisJSON/RedisJSON#1475 JSON.CLEAR does not error if more than one path is specified (MOD-13109).

#14608 Reply copy-avoidance path to reduce memory copies for bulk string replies.
#14595 Hash: unify field name and value into a single struct.
#14701 Sorted set: unify score and value into a single struct.
#14662 Optimize listpack iterator on hash fields.
#14699 Optimize set commands with expiration.
#14700 Optimize prefetching.
#14715 Optimize prefetch sizing logic.
#14636 Optimize ZRANK.
#14676 Utilize hardware clock by default on ARM AArch64.
#14575 Disable RDB compression when diskless replication is used.

#14445
- RM_CreateKeyMetaClass - define a new key-metadata class.
- RM_ReleaseKeyMetaClass - release a key-metadata class.
- RM_SetKeyMeta - attach or update a metadata value for a key under a specific metadata-key class.
- RM_GetKeyMeta - get a metadata value for a key under a specific metadata-key class.

#14624 maxmemory-policy: new eviction policies: volatile-lrm, allkeys-lrm.
#14615 stream-idmp-duration, stream-idmp-maxsize - defaults for streams idempotent production.
#14610 tls-auth-clients-user TLS certificate-based automatic client authentication.
#14596 flushdb option for repl-diskless-load: always flush the entire dataset before diskless load.

#14610 acl_access_denied_tls_cert - failed TLS certificate–based authentication attempts.

Redis Query Engine: In case of load rebalancing operations (such as Atomic Slot Migration) taking place during the lifetime of a cursor, there is a chance that some results may be missing.