v2.6.7

## v2.6.7

Release date: December 4, 2025

| Milvus Version | Python SDK Version | Node.js SDK Version | Java SDK Version | Go SDK Version |
|:-------------- |:------------------|:--------------------|:-----------------|:---------------|
| 2.6.7          | 2.6.4             | 2.6.5               | 2.6.10            | 2.6.1          |

Milvus 2.6.7 is a critical stabilization update for the 2.6.x series. This release focuses on hardening the system against distributed failures and optimizing resource utilization under high load. With significant improvements in I/O handling, memory management, and Kubernetes integration, we strongly recommend all production users upgrade to this version to ensure greater reliability and smoother operation at scale.

### Features

- Added `/livez` endpoint to support Kubernetes native liveness probes, improving container orchestration stability ([#45481](https://github.com/milvus-io/milvus/pull/45481)).
- Added support for **GroupBy** operations on `TIMESTAMPZ` fields, enhancing time-series analytics capabilities ([#45763](https://github.com/milvus-io/milvus/pull/45763))
- Supported `mmap` for JSON shredding's shared key indices to reduce RAM footprint ([#45861](https://github.com/milvus-io/milvus/pull/45861))

### Improvements

- Supported DML request forwarding in the Proxy to improve write availability and routing resilience ([#45922](https://github.com/milvus-io/milvus/pull/45922)).
- Upgrade etcd to v3.5.23 to address consensus stability and performance regressions ([#45953](https://github.com/milvus-io/milvus/pull/45953)).
- Added robust error handling for Etcd server crashes to prevent cascading component failures ([#45633](https://github.com/milvus-io/milvus/pull/45633)).
- Reduced Etcd load by removing expensive watchers for simple session liveness checks ([#45974](https://github.com/milvus-io/milvus/pull/45974)).
- Enhanced the WAL retention strategy to better balance disk usage with data recovery safety ([#45784](https://github.com/milvus-io/milvus/pull/45784)).
- Supported asynchronous write syncing for logs to prevent disk I/O blocking from affecting the main execution path ([#45806](https://github.com/milvus-io/milvus/pull/45806)).
- Enforced Buffered I/O usage for high-priority load tasks to optimize OS page cache utilization and throughput ([#45958](https://github.com/milvus-io/milvus/pull/45958)).
- Optimized `mmap` strategy to map group chunks in a single system call, reducing kernel overhead during segment loading ([#45893](https://github.com/milvus-io/milvus/pull/45893)).
- Improved the accuracy of memory estimation for JSON shredding to prevent OOM kills or under-utilization ([#45876](https://github.com/milvus-io/milvus/pull/45876)).
- Refined segment load estimation to account for both eviction and warmup states ([#45891](https://github.com/milvus-io/milvus/pull/45891)).
- Added granular cancellation checks in query operators to allow faster termination of aborted or timed-out queries ([#45894](https://github.com/milvus-io/milvus/pull/45894)).
- Removed redundant resource type checks in file resource configuration ([#45727](https://github.com/milvus-io/milvus/pull/45727)).

### Bug fixes

- Interleaved Go and C++ logs into a unified stream to provide a correct chronological view for debugging ([#46005](https://github.com/milvus-io/milvus/pull/46005)).
- Resolved a race condition where `LastConfirmedMessageID` could be incorrect under high concurrency writes ([#45874](https://github.com/milvus-io/milvus/pull/45874)).
- Fixed a calculation error in aggregating `allsearchcount` from multiple search results ([#45904](https://github.com/milvus-io/milvus/pull/45904)).
- Fixed Term expressions to correctly handle string containment logic within JSON arrays ([#45956](https://github.com/milvus-io/milvus/pull/45956)).
- Replaced `json.doc()` with `json.dom_doc()` in `JSONContainsExpr` to fix parsing behaviors and improve performance ([#45786](https://github.com/milvus-io/milvus/pull/45786)).
- Fixed a panic in Standby MixCoord components during the shutdown sequence ([#45898](https://github.com/milvus-io/milvus/pull/45898)).
- Fixed the leader checker to ensure segment distribution is correctly synchronized to Read-Only nodes ([#45991](https://github.com/milvus-io/milvus/pull/45991)).
- Ensured `HandleNodeUp` is triggered during node re-watching to maintain correct load balancing topology ([#45963](https://github.com/milvus-io/milvus/pull/45963)).
- Implemented fallback to remote WAL storage if local WAL storage becomes unavailable ([#45754](https://github.com/milvus-io/milvus/pull/45754)).
- Added `EmptySessionWatcher` to prevent panics when running in IndexNode binding mode ([#45912](https://github.com/milvus-io/milvus/pull/45912)).
- Ensured memory state consistency when recovering broadcast tasks from protocol buffers ([#45788](https://github.com/milvus-io/milvus/pull/45788)).
- Addressed thread-safety issues in SegCore collection schema updates ([#45618](https://github.com/milvus-io/milvus/pull/45618)).
- Enforced Access Control (RBAC) checks for `ListImport` and `GetImportProgress` APIs ([#45862](https://github.com/milvus-io/milvus/pull/45862)).
- Fixed a bug where BulkImport would fail if the input contained an empty struct list ([#45692](https://github.com/milvus-io/milvus/pull/45692)).