Redis Open Source 8.4 release notes
===================================

--------------------------------------------------------------------------------
Upgrade urgency levels:

LOW:      No need to upgrade unless there are new features you want to use.
MODERATE: Program an upgrade of the server, but it's not urgent.
HIGH:     There is a critical bug that may affect a subset of users. Upgrade!
CRITICAL: There is a critical bug affecting MOST USERS. Upgrade ASAP.
SECURITY: There are security fixes in the release.
--------------------------------------------------------------------------------

The release notes contain PRs from multiple repositories:

#n - Redis (https://github.com/redis/redis)
#Qn = Query Engine (https://github.com/RediSearch/RediSearch)
#Jn = JSON (https://github.com/RedisJSON/RedisJSON)
#Tn = Time Series (https://github.com/RedisTimeSeries/RedisTimeSeries)
#Pn = Probabilistic (https://github.com/RedisBloom/RedisBloom)


================================================================================
Redis 8.4.3    Released Tue 5 May 2026 16:00:00 IST
================================================================================

Update urgency: `SECURITY`: There are security fixes in the release.

### Security fixes

- (CVE-2026-23479) Use-After-Free in unblock client flow may lead to Remote Code Execution.
- (CVE-2026-25243) Invalid memory access in `RESTORE` may lead to Remote Code Execution
- (CVE-2026-23631) Lua Use-After-Free may lead to remote code execution
- (CVE-2026-25588) Invalid memory access in `RESTORE` may lead to Remote Code Execution (Time Series)
- (CVE-2026-25589) Invalid memory access in `RESTORE` may lead to Remote Code Execution (Probabilistic)

### Bug fixes

- `SUBSCRIBE`, `PSUBSCRIBE`, `SSUBSCRIBE`: crash on OOM (RED-167788)
- `CONFIG SET`: some settings allow invalid characters (RED-167787)
- `SCRIPT DEBUG`: potential crash on scripts (RED-175507)
- `VADD`: crash or buffer overflow on large `REDUCE` value (RED-170921)
- `VSET`: crash on huge allocations (MOD-12678)
- Potential crash on disconnections and TLS failures (Time Series) (MOD-14850)
- #Q8744 Crash when many keys receive expirations under heavy TTL activity (MOD-14500)
- #Q8849 HNSW vector index memory growth under high-churn workloads until shard restart (MOD-13761)
- #Q8258 `FT.HYBRID` `VSIM RANGE` + `FILTER` incorrectly returns zero results (MOD-13885)
- #Q9183 `FT.PROFILE HYBRID` returns an empty reply (MOD-14778)
- #Q9048 `FT.PROFILE` output is inconsistent when a profiled value is missing (MOD-10560)
- #Q8792 `FT.EXPLAIN` does not lock, causing a race with concurrent index changes (MOD-14461)
- #Q8384 Crash when indexing negative zero (-0.0) (MOD-13904)
- #Q8596 `FILTER` returns inconsistent results with multiple indexes sharing field aliases (MOD-14063)
- #Q8661 `FILTER` behavior depends on property order in the expression (MOD-14065)
- #Q8598 Filter expressions are evaluated for indexes that do not match the document type (MOD-14064)
- #Q8597 Documents are inconsistently included or excluded depending on the indexing path taken (MOD-13948)
- #Q8595 `RENAME` notification handler loads the wrong key, causing stale index entries after a rename (MOD-14062)
- #Q9011 `PERSIST` and `HPERSIST` notifications are not reflected in index expiration tracking (MOD-14800)
- #Q9080 `FT.SPELLCHECK` treats `PARAMS` placeholders as literal terms instead of resolving them (MOD-10596)
- #Q8461 GC out-of-memory on replica shards leaves the replica in an inconsistent state (MOD-14066)
- #Q9091 Race condition in `FT.HYBRID` causes intermittent failures under concurrent hybrid query load (MOD-14732)
- #Q9161 Coordinator deadlock under mixed `FT.SEARCH` and `FT.AGGREGATE` load (MOD-14268)
- #Q9165 Crash on `FT.SEARCH` when topology validation fails (for example, some nodes unreachable) (MOD-14475)
- #Q8394 `FT.SEARCH` fails with "Query requires unavailable slots" after shard restart or failover (MOD-13828)
- #Q8452 `FT.INFO`-style output no longer reports zero-index summary data when no indices exist (MOD-14080)
- #Q9077 `FT.CREATE` now rejects schema definitions with invalid option combinations at creation time (MOD-14655)

### Metrics

- #Q8210, #Q8231 `FT.PROFILE`: added queue time tracking (MOD-13602)


================================================================================
Redis 8.4.2    Released Mon 23 Feb 2026 10:00:00 IST
================================================================================

SECURITY: There is a security fix in the release

### Security fixes

- A user can manipulate data read by a connection by injecting \r\n sequences into a Redis error reply


================================================================================
Redis 8.4.1    Released Sun 8 Feb 2026 9:00:00 IST
================================================================================

Update urgency: `SECURITY`: There are security fixes in the release.

### Security fixes

- #T1837, #J1474 Hide Personally Identifiable Information from server log
- #P936 Cuckoo filter: crash on RDB load on 0 buckets (MOD-11593)
- #P945 Bloom filter: crash on RDB load on large number of filters (MOD-11590)

### Bug fixes

- #14637 Atomic slot migration: wrong adjacent slot range behavior
- #14567 Atomic slot migration: support delay trimming slots after finishing migrating slots
- #T1864 Atomic slot migration: time series limitations (MOD-13611)
- #14746 `CLUSTER SLOT-STATS`: Fix few memory tracking bugs
- #Q6973 Correct empty string token counting in byteOffset calculations to ensure accurate text position tracking (MOD-11233)
- #Q6995 Prevent `FT.INFO` command fanout to replicas to reduce unnecessary cluster traffic
- #Q7154 Display Background Indexing OOM warning in `FT.AGGREGATE` when memory limits are approached (MOD-11817)
- #Q7219 Resolve concurrency issue in `FT.AGGREGATE`reducer that caused intermittent errors (MOD-12243)
- #Q7255 Correct `BM25STD` underflow wraparound to prevent incorrect scoring (MOD-12223)
- #Q7264 Ensure accurate `totalDocsLen` updates to maintain correct document statistics (MOD-12234)
- #Q7275 Report used memory as unsigned long to prevent overflow (RED-169833)
- #Q7350 `FT.CREATE` with LeanVec parameters on non-Intel architectures (RED-176382)
- #Q7371 Validate `search-min-operation-workers` min value correctly (MOD-12383)
- #Q7430 Prevent coordinator deadlock in `FT.HYBRID` queries by avoiding index read lock (MOD-12489)
- #Q7435 Ensure full profile output on timeout with `RETURN` policy in `FT.PROFILE` (MOD-12320)
- #Q7446 Remove outdated validation from debug aggregate in cluster mode (MOD-12435)
- #Q7455 Ensure internal cursors are deleted immediately in cluster mode (MOD-12493)
- #Q7458 Correct GC regression that caused stability issues (MOD-12538)
- #Q7460 Prevent potential double-free on error path in Fork GC (MOD-12521)
- #Q7499 Propagate `HGETALL` command in HDT mode (MOD-12662)
- #Q7534 Reduce number of worker threads asynchronously to prevent performance degradation (MOD-12252, MOD-11658)
- #Q7553 Handle `WITHSCORES` correctly when SCORE is sent alone without extra fields in coordinator (MOD-12647)
- #Q7560 Properly handle connection closing in IO thread at shutdown and fix searchRequestCtx freeing on error (MOD-12699)
- #Q7685 Resolve cursor logical leak that could lead to resource exhaustion (MOD-12807)
- #Q7710 Support for `WITHCOUNT` in `FT.AGGREGATE` (MOD-11751)
- #Q7794 Correctly handle binary data with embedded NULLs to prevent crashes (MOD-13010)
- #Q7812 Correct SVS GC for no-workers case (MOD-12983)
- #Q7815 Fix command routing in cluster mode by not relying on shard index (MOD-13049)
- #Q7823 Support vector blob only through parameter in `FT.HYBRID`(MOD-13123)
- #Q7873 Handle warnings in empty `FT.AGGREGATE` replies in cluster mode (MOD-12640)
- #Q7897 Remove asserts from DownloadFile to prevent crash (MOD-13096)
- #Q7901 Support multiple warnings in reply to prevent warning loss (MOD-13252)
- #Q7903 Eliminate memory leak in `FT.HYBRID` queries with Active-Active enabled (MOD-13143)
- #Q7886 Remove non-TEXT fields from spec's keys dictionary to prevent incorrect field handling (MOD-13150)
- #Q7905 Remove non-TEXT fields from spec's keys dictionary and refactor keys dict (MOD-13150, MOD-13151)
- #Q7978 Avoid using negative key position values during command registration (MOD-13332)
- #Q8052 Resolve incorrect results when using `LOAD *` with `FT.HYBRID` (MOD-12736, MOD-13556)
- #Q8083 Correct `FULLTEXT` field metric count accuracy (MOD-13432)
- #Q8089 Handle edge case in clusterset (MOD-13562)
- #Q8151 Correct `FT.PROFILE` shard total profile time calculation (MOD-13735, MOD-13181)
- #Q8153 Resolve config registration issue (RED-171841)
- #Q7449 Ensure `FT.HYBRID` respects timeout settings (MOD-11004)
- #Q7238 Initialize GIL_TIME properly for `FT.PROFILE` (MOD-12553)
- #Q7453 Error behavior on early bailout and split OOM warning for shard and coordinator (MOD-12449)
- #Q7615 Parameter `numDocs` from non-optimized Wildcard iterator (MOD-12392)
- #Q7165 (Redis Enterprise only) `FT.DROPINDEX` as touches-arbitrary-keys for proper cluster handling causing crash on A-A (MOD-11090)
- #Q7023 (Redis Enterprise only) Ensure all `FT.SUG*` commands are hashslot-aware to prevent cluster routing errors (MOD-11756)

### Performance and resource utilization improvements

- #Q7496 Vector search performance improvements (MOD-12011, MOD-12063, MOD-12629, MOD-12346)
- #Q7519 Reduce number of worker threads asynchronously to improve resource utilization (MOD-12252, MOD-11658)
- #Q7694 Use asynchronous jobs in GC for SVS to reduce blocking (MOD-12668)
- #Q7730 Support `filter_policy` and `batch_size` parameters for vector similarity search tuning (MOD-13007, MOD-12371)
- #Q7782 Resolve SVS GC failures when worker threads are disabled (MOD-12983)
- #Q7572 Implement ASM state machine on notifications (MOD-12170)
- #Q7829 ASM-aware search flow for Active-Active deployments (MOD-12171, MOD-12169)
- #Q7589 Support multiple slot ranges in `search.CLUSTERSET` for flexible cluster topology updates (MOD-11657)
- #Q7862 Support subquery count in `FT.HYBRID` (MOD-11858, MOD-13146)
- #Q7893 Request policy support for cursor operations (MOD-13146, MOD-9573, MOD-8104)
- #Q8087 Warning when cursor may give inaccurate results due to Active-Active replication (MOD-12899)
- #Q7445 Remove outdated validation from Debug Aggregate in cluster mode (MOD-12435)
- #Q7384 Reduce index load from RDB temporary memory overhead (MOD-12212)

### Metrics

- #Q7960 Persist query warnings across cursor reads (MOD-12984)
- #Q7612 Track `maxprefixexpansions` errors and warnings in info (MOD-12417)
- #Q7872 Handle warnings in empty `FT.AGGREGATE` replies in cluster mode (MOD-12640)
- #Q7900 Support multiple warnings in reply (MOD-13252)
- #Q7576 Track OOM errors and warnings in info (MOD-12418)
- #Q7507 Track timeout errors and warnings in info (MOD-12419)
- #Q7341 Rename `FT.PROFILE` counter fields for clarity (MOD-6056)
- #Q7436, #Q7427 Enhance `FT.PROFILE` with vector search execution details (MOD-12263)
- #Q7573 Debug support for `FT.PROFILE` command (MOD-12627)
- #Q7736 Add `Internal cursor reads` metric to cluster `FT.PROFILE` output (MOD-12414)
- #Q7692 Declare query error struct on `_FT.CURSOR PROFILE` (MOD-12955)
- #Q7848 Store and display shard ID in profile output (MOD-12321)
- #Q7422 Track syntax and argument errors in query error metrics (MOD-12416)
- #Q7552 Add `active_io_threads` metric (MOD-12069, MOD-12695)
- #Q7622 Add `active_coord_threads` metric (MOD-12694, MOD-12069)
- #Q7564 Add `active_worker_threads` metric (MOD-12694, MOD-12069)
- #Q7626 Add `*_pending_jobs` metrics for job queues (MOD-12069)
- #Q7658 Add pending workers admin jobs metric (MOD-12069, MOD-12791)
- #Q7731 Add `active_topology_update_threads` metric (MOD-12069, MOD-12790)
- #Q7760 Extend indexing metrics for more detailed performance data (MOD-12070)

### Configuration parameters

- #Q7083 Add default scorer configuration option (MOD-10037)


===========================================================
8.4 GA (v8.4.0)    Released Tue 18 Nov 2025 15:00:00 IST
===========================================================

This is the General Availability release of Redis 8.4 in Redis Open Source.

### Major changes compared to 8.2

- `DIGEST`, `DELEX`; `SET` extensions - atomic compare-and-set and compare-and-delete for string keys
- `MSETEX` - atomically set multiple string keys and update their expiration
- `XREADGROUP` - new `CLAIM` option for reading both idle pending and incoming stream entries
- `CLUSTER MIGRATION` - atomic slot migration
- `CLUSTER SLOT-STATS` - per-slot usage metrics: key count, CPU time, and network I/O
- Redis query engine: `FT.HYBRID` - hybrid search and fused scoring
- Redis query engine: I/O threading with performance boost for search and query commands (FT.*) 
- I/O threading: substantial throughput increase (e.g. >30% for caching use cases (10% `SET`, 90% `GET`), 4 cores)
- JSON: substantial memory reduction for homogeneous arrays (up to 91%)

### Binary distributions

- Alpine and Debian Docker images - https://hub.docker.com/_/redis
- Install using snap - see https://github.com/redis/redis-snap
- Install using brew - see https://github.com/redis/homebrew-redis
- Install using RPM - see https://github.com/redis/redis-rpm
- Install using Debian APT - see https://github.com/redis/redis-debian

### Operating systems we test Redis 8.4 on

- Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat)
- Rocky Linux 8.10, 9.5
- AlmaLinux 8.10, 9.5
- Debian 12 (Bookworm), Debian 13 (Trixie)
- macOS 13 (Ventura), 14 (Sonoma), 15 (Sequoia)

### Bug fixes (compared to 8.4-RC1)

- #14524 `XREADGROUP CLAIM` returns strings instead of integers
- #14529 Add variable key-spec flags to SET IF* and DELEX
- #P928 Potential memory leak (MOD-11484)
- #T1801, #T1805 macOS build failures (MOD-12293)
- #J1438 `JSON.NUMINCRBY` - wrong result on integer array with non-integer increment (MOD-12282)
- #J1437 Thread safety issue related to ASM and shared strings (MOD-12013)

### Performance and resource utilization improvements (compared to 8.4-RC1)

- #14480, #14516 Optimize `XREADGROUP`

### known bugs and limitations

- When executing `FT.SEARCH`, `FT.AGGREGATE`, `FT.CURSOR`, `FT.HYBRID`, `TS.MGET`, `TS.MRANGE`, `TS.MREVRANGE` and `TS.QUERYINDEX` while an atomic slot migration process is in progress, the results may be partial or contain duplicates
- `FT.PROFILE`, `FT.EXPLAIN` and `FT.EXPLACINCLI` doesn’t contain the `FT.HYBRID` option
- Metrics from `FT.HYBRID` command aren’t displayed on `FT.INFO` and `INFO`
- Option `EXPLAINSCORE`, `SHARD_K_RATIO`, `YIELD_DISTANCE_AS` and `WITHCURSOR` with `FT.HYBRID` are not available
- Post-filtering (after `COMBINE` step) using FILTER is not available
- Currently the default response format considers only `key_id` and `score`, this may change for delivering entire document content

===========================================================
8.4-RC1 (v8.3.240)    Released Tue 4 Nov 2025 10:00:00 IST
===========================================================

This is the first Release Candidate of Redis 8.4 in Redis Open Source.

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

### Binary distributions

- Alpine and Debian Docker images - https://hub.docker.com/_/redis
- Install using snap - see https://github.com/redis/redis-snap
- Install using brew - see https://github.com/redis/homebrew-redis
- Install using RPM - see https://github.com/redis/redis-rpm
- Install using Debian APT - see https://github.com/redis/redis-debian

### Operating systems we test Redis 8.4 on

- Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat)
- Rocky Linux 8.10, 9.5
- AlmaLinux 8.10, 9.5
- Debian 12 (Bookworm), Debian 13 (Trixie)
- macOS 13 (Ventura), 14 (Sonoma), 15 (Sequoia)

### New Features (compared to 8.2.3)

- #14414 New command: `CLUSTER MIGRATION` - atomic slot migration
- #14435 New commands: `DELEX`, `DIGEST`; `SET` extensions - atomic compare-and-set and compare-and-delete for string keys
- #14434 New command: `MSETEX` - set multiple keys and update their expiration
- #14402 `XREADGROUP` - add `CLAIM min-idle-time` to consume both idle pending entries and incoming entries
- #14058 Add auto-repair options for broken AOF tail on startup
- #14296 Support decoding JSON empty array as a Lua array
- #T1773 `HELP` and `COMMAND DOCS` now support time series commands (MOD-8133)
- #P892 `HELP` and `COMMAND DOCS` now support probabilistic commands (MOD-8133)
- #Q7076, #Q6857 New Command: `FT.HYBRID` - hybrid queries with RRF and LINEAR combination 
- #Q7022 Support index updates when atomic slot migrations occurs
- #Q6313 Support multiple I/O threads for RQE cluster manager - Coordinator (MOD-10562)

### Bug fixes (compared to 8.2.3)

- #14423 Potential infinite loop when a stream is corrupted
- #14420 Shutdown blocked client not being properly reset after shutdown cancellation
- #14417 `CLUSTER FORGET` - heap-buffer-overflow
- #14415 Potential crash in `lookupKey()` when `executing_client` is NULL
- #T1776 Potential crash on `TS.RANGE` with `ALIGN +`, `AGGREGATION twa` and `EMPTY` (MOD-11620, MOD-10484)

### Performance and resource utilization improvements (compared to 8.2.3)

- #14440 Lookahead prefetching - parse multiple commands in advance through a lookahead pipeline
- #14309 Optimize `BITCOUNT` with AVX2 and AVX512 popcount implementations
- #14227 Optimize `BITCOUNT` with Arm Neon SIMD vectorization
- #14428 Optimize HyperLogLog with branchless comparisons and Arm Neon SIMD vectorization
- #14222 Optimize Vector set `VADD` and `VSIM` with AVX2 and AVX512 dot product implementations
- #JIJSON9 JSON - memory footprint improvement by using homogeneous arrays (MOD-9511)
- #JIJSON7 JSON - memory footprint improvement by inlining short strings (MOD-9511)

### Configuration parameters

- #14058 `aof-load-corrupt-tail-max-size` - maximum corrupted tail size (in bytes) to attempt to repair automatically
- #14296 `decode_array_with_array_mt` - Lua: control how empty JSON arrays are handled
- #14440 `lookahead` - runtime-configurable lookahead depth (default: 16)
- #Q7065 `search-default-scorer` - default text and tag scorer (new default is BM25STD)
- #Q6769 `search-on-oom` - behavior when OOM event occurs in the query time, supports 3 values:
  - `IGNORE` - queries run despite OOM, not recommended for heavy result sets (current behaviour)
  - `FAIL` - query execution fails if any node is in OOM state at start
  - `RETURN` - returns partial results if OOM is detected in only some cluster nodes (default)
- #Q6313 `search-io-threads` - allow setting the comms threads used by the cluster manager - coordinator (default: 20)

### known bugs and limitations

- When executing `FT.SEARCH`, `FT.AGGREGATE`, `FT.CURSOR`, `FT.HYBRID`, `TS.MGET`, `TS.MRANGE`, `TS.MREVRANGE` and `TS.QUERYINDEX` while an atomic slot migration process is in progress, the results may be partial or contain duplicates
- `FT.PROFILE`, `FT.EXPLAIN` and `FT.EXPLACINCLI` doesn’t contain the `FT.HYBRID` option
- Metrics from `FT.HYBRID` command aren’t displayed on `FT.INFO` and `INFO`
- Option `EXPLAINSCORE`, `SHARD_K_RATIO`, `YIELD_DISTANCE_AS` and `WITHCURSOR` with `FT.HYBRID` are not available
- Post-filtering (after `COMBINE` step) using FILTER is not available
- Currently the default response format considers only `key_id` and `score`, this may change for delivering entire document content

