NATS v2.12.12

A maintenance release focused heavily on hardening and reliability. It fixes several edge-case panics in MQTT and JetStream, resolves potential data corruption in compressed filestores, and ensures consistent permission updates across accounts. Monitoring is also tightened by removing legacy JSONP support.

Critical Stability and Data Integrity Fixes — This release addresses several critical failure modes including panics in MQTT handling, JetStream data store corruption in encrypted/compressed blocks, and Raft consensus desyncs. These fixes significantly improve the uptime and data integrity of production clusters.

Hardened Authentication and MQTT Security — By fixing vulnerabilities in MQTT packet handling and ensuring account permission refreshes actually take effect, the server is better protected against memory exhaustion attacks and unauthorized access during configuration changes.

Improved JetStream and Cluster Consistency — Key fixes in JetStream ensure that streams do not desync when limits are exceeded and that consumer filters remain consistent, which is vital for users relying on NATS for reliable message delivery and ordering in microservices.