Version 1.0 (The Seven Mile Journey):

1.Full MQTT V3.1/3.1.1 Protocol Specifications Support
2.Massively scalable - Scaling to 1 million connections on a single server
3.Distributed - Route MQTT Messages among clustered or bridged broker nodes
4.Extensible - LDAP, MySQL, PostgreSQL, Redis Authentication/ACL Plugins

Version 2.0 “West of West Lake”:

1.First of all, the EMQ broker now supports Shared Subscription and Local Subscription.
2.Supports CoAP(RFC 7252) and MQTT-SN protocol/gateway.
3.Adopt a more user-friendly k = v syntax for the new configuration file.
4.Add more hooks and new plugins, integrate with HTTP, LDAP, Redis, MySQL, PostgreSQL and MongoDB.
5.Cross-platform Builds and Deployment. Run the broker on Linux, Unix, Windows, Raspberry Pi and ARM platform.

Version 2.1:

Release Date: 2017-02-24
1.Tuning GC
2.Dashboard Plugin

Version 2.2:

Release Date: 2017-05-05
Many new features including Web Hook, Lua Hook and Proxy Protocol have been released
1.MQTT Listeners
Support to configure multiple MQTT TCP/SSL listeners for one EMQ node
-- External TCP 1883 --> |     |
                         | EMQ | -- Internal TCP 2883 --> Service
-- External SSL 8883-->  |     |
2.Proxy Protocol V1/2
3.Web Hook Plugin
4.Lua Hook Plugin
5.Improve the Auth/ACL Chain
6.Support bcrypt password hash

Version 2.3:

1.new HTTP Managment API, and supports Hot configuration of some parameters and plugins
2.Node Discovery and Autocluster:static,mcast,dns,etcd,k8s