MQTTnet/ReleaseNotes.md

• [Core] Improved memory management when working with large payloads.
• [Client] The OS will now choose the best TLS version to use. It is no longer fixed to 1.3 etc. (thanks to @patagonaa, #1271).
• [Client] Exposed user properties and reason string in subscribe result.
• [Client] Exposed user properties and reason string in unsubscribe result.
• [Server] Added support for returning individual subscription errors (#80 thanks to @jimch)
• [Server] Improved topic filter comparisons (support for $).
• [Server] Added more MQTTv5 response information to all interceptors (BREAKING CHANGE!).
• [Server] Improved session management for MQTT v5 (#1294, thanks to @logicaloud).
• [Server] All interceptors and events are migrated from interfaces to simple events. All existing APIs are availble but must be migrated to corresponding events.
• [Server] Removed all interceptor and event interfaces including the delegate implementations etc.
• [Server] Renamed a lot of classes and adjsuted namespaces.
• [Server] Introduced a new queueing approach for internal message process (packet bus).