Version 2.3.5

Release Date: 2018-03-03

Bugfix and Enhancements

Feature: Add etc/ssl_dist.conf file for erlang SSL distribution (emq-relx#178)

Feature: Add node.ssl_dist_optfile option and etc/ssl_dist.conf file (#1512)

Feature: Support Erlang Distribution over TLS (#1512)

Improve: Tune off the ‘tune_buffer’ option for external MQTT connections (#1512)


Clean registered topics if mqtt-sn client send a 2nd CONNECT in connected state (#76)

Upgrade the esockd library to v5.2.1 (#76)


Remove ‘password’ param from ACL and superuser requests (#66)

Version 2.3.4

Release Date: 2018-01-29

Bugfix and Enhancements

Feature: Forward real client IP using a reverse proxy for websocket (#1335)

Feature: EMQ with link local ipv6 address not responding to ping (#1460)

Feature: Add PROTO_DIST_ARG flag to support clustering via IPv6 address. (#1460)

Bugfix: retain bit is not set when publishing to clients (when it should be set). (#1461)

Bugfix: Can’t search topic on web dashboard (#1473)


Bugfix: CONNACK is not always sent to the client (emq-sn#67)

Bugfix: Setting the port to ::1:2000 causes error (emq-sn#66)

Version 2.3.3

Release Date: 2018-01-08

Bugfix and Enhancements

Add a full documentation for emq.conf and plugins.

Repair a dead link in README - missing emq-lwm2m. (#1430)

Subscriber with wildcard topic does not receive retained messages with sub topic has $ sign (#1398)

Web Interface with NGINX Reverse Proxy not working. (#953)


Add dashboard.default_user.login, dashboard.default_user.password options to support configuring default admin.


The emq-modules rewrite config is not right. (#35)


Upgrade alpine to 3.7 (#31)


Support ARM Platform (#12)

Version 2.3.2

Release Date: 2017-12-26

Bugfix and Enhancements

Support X.509 certificate based authentication (#1388)

Add proxy_protocol, proxy_protocol_timeout options for ws/wss listener.

Cluster discovery etcd nodes key must be created manually. (#1402)

Will read an incorrect password at the last line of emq_auth_username.conf (#1372)

How can i use SSL/TLS certificate based client authentication? (#794)

Upgrade the esockd library to v5.2.


Improve the parser of proxy protocol v2.

Add ‘send_timeout’, ‘send_timeout_close’ options.

Rename esockd_transport:port_command/2 function to async_send/2.

Add test case for esockd_transport:async_send/2 function.

Add esockd_transport:peer_cert_subject/1, peer_cert_common_name/1 functions.


Update depends on emqtt/mysql-otp.

Fixed the issue that Cannot connect to MySQL 5.7 (#67).


Fix mergeconf/3 appending line break error. (#152)


Fix crash in emq_sn_gateway:transform() function which handles SUBACK. (#57)

Define macro SN_RC_MQTT_FAILURE. (#59)


Filter auth_failure client for disconnected hook. (#30)

Version 2.3.1

Release Date: 2017-12-03

Bugfix and Enhancements

Remove the unnecessary transactions to optimize session management.

Should not exit arbitrarily when clientid conflicts in mnesia.

Change the default value of ‘mqtt.session.enable_stats’ to ‘on’.

The DUP flag should be set to 0 for all QoS0 messages. (emqttd#1319)

Fix the ‘no function clause’ exception. (emqttd#1293)

The retained flags should be propagated for bridge. (emqttd#1293)

The management API should listen on (emqttd#1353)

Fast close the invalid websocket in init/1 function.

erlang:demonitor/1 the reference when erasing a monitor. (emqttd#1340)


Don’t clean the retain flag after the retained message is stored.

Add three CLIs for the retainer plugin. (emq-retainer#38)


Refactor(priv/www): improve the routing page. (emq-dashboard#185)


Turn off the subscription module by default. (emq-modules#26)


Add an integration test case for sleeping device.

Do not send will topic if client is kicked out.

Prevent crash information in log when emq_sn_gateway getting timeout, since it is a possible procedure.


Support node cookie value with = characters. (emq-relx#146)


Improve Req:get(peername) funciton to support x-forwarded-for and x-remote-port. (emqtt/mochiweb#9)

Version 2.3.0 “Passenger’s Log”

Release Date: 2017-11-20

EMQ 2.3.0 is available now! EMQ R2.3.0 improved the PubSub design to avoid race-condition issue and optimized the message routing efficiency. The self-signed certificates for SSL released with EMQ has been updated. This release also comes with a new dashboard theme and improvement of API design.

Bugfix and Enhancements

Fixed the issue that Retained message is not sent for Subscribe to existing topic. (emqttd#1314)

Fixed the issue that The DUP flag MUST be set to 0 for all QoS0 messages.(emqttd#1319)

Improve the pubsub design and fix the race-condition issue. (emqttd#PR1342)

Crash on macOS High Sierra (emqttd#1297)

emq-dashboard Plugin (emq-dashboard#PR174)

Upgraded the ‘subscriptions’ RESTful API.

Improvement of the auth failure log. (emq-dashboard#59)

emq-coap Plugin (emq-coap#PR61)

Replaced coap_client with er_coap_client.

Fixed: correct the output format of coap_discover() to enable “.well-known/core”.

Refactor the coap_discover method.


Upgraded the bin/nodetool script to fix the rpcterms command.

emq-web-hook Plugin

Fixed the emq_web_hook plugin getting username from client.connected hook. (emq-web-hook#19)

emq-auth-jwt Plugin(emq-auth-jwt#PR15)

Added test cases for emq_auth_jwt.

Fixed jwt:decode/2 functions’s return type.

emq-auth-mongo Plugin(emq-auth-mongo#PR92)

Updated the default MongoDB server configuration.

Version 2.3-rc.2

Release Date: 2017-10-22

Change the default logging level of trace CLI. (emqttd#1306)

emq-dashboard Plugin (emq-dashboard#164)

Fix the ‘Status’ filters of plugins’s management.

Fix the URL Redirection when deleting an user.

Compatible with IE,Safari,360 Browsers.

Version 2.3-rc.1

Release Date: 2017-10-12

Fixed the issue that invalid clients can publish will message. (emqttd#1230)

Fixed Dashboard showing no stats data (emqttd#1263)

Fixed a rare occurred building failure (emqttd#1284)

Support Persistence Logs for longer time (emqttd#1275)

Fix for users APIs (emqttd#1289)

Changed passwd_hash/2 function’s return type (emqttd#1289)

emq-dashboard Plugin (emq-dashboard#154)

Improved the Dashboard Interface of Monitoring/Management/Tools.

Allow switching dashboard themes.

Supoort both EN and CN languages.

Version 2.3-beta.4

Release Date: 2017-09-13


Released a new sexy dashboard.

Add more RESTful APIs for manangement and monitoring.

Configuring the broker through CLI or API without having to restart.


Job for emqttd.service failed because the control process exited with error code. (emqttd#1238)

Travis-CI Build Failing (emqttd#1221)

Https listener of Dashboard plugin won’t work (emqttd#1220)

Service not starting on Debian 8 Jessie (emqttd#1228)


  1. Support switching to other clustered node.
  2. Configure and reboot the plugins on the dashboard.
  3. A login page to replace the basic authentication popup window.


1.Try to clarify the relationship between coap and mqtt in EMQ. (emq-coap#54).

2.Fix crashes in coap concurrent test(gen-coap#3).

Version 2.3-beta.3

Release Date: 2017-08-21


Add HTTP API for hot configuration.


  1. Parse ‘auth.mysql.password_hash’ error when hot configuration reload (emq-auth-mysql#68)
  2. Set ‘auth.pgsql.server’ error when hot configuration reload (emq-auth-pgsql#67)
  3. Set ‘auth.redis.server’ and ‘auth.redis.password_hash’ error when hot configuration reload (emq-auth-redis#47)
  4. Fixed the issue that when deleting retained message subscribed clients are not notified (emqttd#1207)
  5. Support more parameters for hot configuration reload:
  • mqtt.websocket_protocol_header = on
  • mqtt.mqueue.low_watermark = 20%
  • mqtt.mqueue.high_watermark = 60%
  • mqtt.client.idle_timeout = 30s
  • mqtt.client.enable_stats = off

Version 2.3-beta.2

Release Date: 2017-08-12

EMQ R2.3-beta.2, a development release, is available now! This release introduces new HTTP Managment API, and supports Hot configuration of some parameters and plugins.

The plugins which support Hot configuration:

  • emq-stomp
  • emq-coap
  • emq-sn
  • emq-lwm2m
  • emq-dashboard
  • emq-retainer
  • emq-recon
  • emq-web-hook
  • emq-auth-jwt
  • emq-auth-http
  • emq-auth-mongo
  • emq-auth-mysql
  • emq-auth-pgsql
  • emq-auth-redis


  1. Introduce new HTTP management API.
  2. Add ClientId parameter for HTTP Publish API.
  3. Allow configuring keepalive backoff.
  4. Remove the fullsweep_after option to lower CPU usage.
  5. Authorize HTTP Publish API with clientId.

emq-sn Plugin (emq-sn#49)

  1. Support CONNECT message in connected/wait_for_will_topic/wait_for_will_msg states.
  2. Clean registered topic for a restarted client.
  3. Bug fix of not clearing buffered PUBLISH messages received during asleep state as those messages are sent to client when client wakes up.

emq-auth-ldap Plugin (emq-auth-ldap#21)

Improve the design LDAP authentication.

emq-coap Plugin (emq-coap#51)

Support CoAP PubSub Specification (

Version 2.3-beta.1

Release Date: 2017-07-24

EMQ R2.3-beta.1 is available now! This release supports automatic cluster node discovery and network partition autoheal. It supports automatically forming clusters of Erlang nodes using different strategies, such as IP Multicast, Etcd and Kubernetes.

Node Discovery and Autocluster

EMQ R2.3 supports node discovery and autocluster with various strategies:

Strategy Description
static Autocluster by static node list
mcast Autocluster by UDP Multicast
dns Autocluster by DNS A Record
etcd Autocluster using etcd
k8s Autocluster on Kubernetes

Network Partition and Autoheal

Enable autoheal of Network Partition by default:

cluster.autoheal = on

When network partition occurs, the following steps are performed to heal the cluster if autoheal is enabled:

  1. Node reports the partitions to a leader node which has the oldest guid.
  2. Leader node create a global netsplit view and choose one node in the majority as coordinator.
  3. Leader node requests the coordinator to autoheal the network partition.
  4. Coordinator node reboots all the nodes in the minority side.

Node down and Autoclean

A down node will be removed from the cluster if autoclean is enabled:

cluster.autoclean = 5m

LWM2M Protocol Support

EMQ-LWM2M is a gateway plugin for EMQ,which implements most LWM2M features. MQTT client is able to access LWM2M device through emq-lwm2m plugin, by sending a command and reading its response.

Lightweight M2M (LWM2M) is a set of protocols defined by the Open Mobile Alliance (OMA) for machine-to-machine (M2M) or Internet of Things (IoT) device management and communications

JWT Authentication

EMQ R2.3 supports JWT(JSON Web Token) Authentication with emq-auth-jwt plugin.

Retainer Plugin

Retainer Plugin support ‘disc_only’ mode to store MQTT retained messages.

Debian 9 Package

EMQ R2.3 released binary package for Debian 9.

Erlang/OTP R20

EMQ R2.3 is compatible with Erlang/OTP R20, and all the binary packages are built on Erlang/OTP R20.

Version 2.2 “Nostalgia”

Release Date: 2017-07-08

Release Name: Nostalgia

EMQ 2.2.0 is available now! EMQ R2.2 supports CoAP(RFC 7252), MQTT-SN protocols completely, and it is extensible with Web Hook, Lua Hook and Elixir Hook.

Feature: Add ‘listeners restart/stop’ CLI command (emqttd#1135)

Bugfix: Exit Code from emqttd_ctl (emqttd#1133)

Bugfix: Fix spec errors found by dialyzer (emqttd#1136)

Bugfix: Catch exceptions thrown from rpc:call/4 (emq-dashboard#128)

Bugfix: Topic has been decoded by gen-coap, no conversion needed (emq-coap#43)

Version 2.2-rc.2

Release Date: 2017-07-03


2.2-rc.2 requires Erlang/OTP R19.3+ to build.

Bugfix and Enhancements

Compatible with Erlang/OTP R20 (emq-relx#77)

CoAP gateway plugin supports coap-style publish & subscribe pattern. (emq_coap#33)

MQTT-SN gateway plugin supports sleeping device (emq_sn#32)

Upgrade esockd and mochiweb libraries to support restarting a listener

Version 2.2-rc.1

Release Date: 2017-06-14

Bugfix and Enhancements

Add a new listener for HTTP REST API (emqttd#1094)

Fix the race condition issue caused by unregister_session/1 (emqttd#1096)

Fix the issue that we cannot remove a down node from the cluster (emqttd#1100)

Passed org.eclipse.paho.mqtt_sn.testing/interoperability tests (emq_sn#29)

Fixed the issue that send http request and return non-200 status code, but AUTH/ACL result is denied (emq-auth-http#33)

Fixed the issue that fail to stop listener (emq_stomp#24)

Support using systemctl to manage emqttd service on CentOS

Version 2.2-beta.3

Release Date: 2017-05-27

Bugfix and Enhancements

Call emit_stats when force GC (emqttd#1071)

Update the default value of ‘mqtt.mqueue.max_length’ to 1000 (emqttd#1074)

Update emq-auth-mongo READEME (emq-auth-mongo#66)

Update default password field (emq-auth-mongo#67)

Upgrade the mongodb library to v3.0.3

Remove ‘check password===undefined && userName!== undefined’ (emq-dashboard#120)

emq_auth_redis Plugin

Support ‘HGET mqtt_user:%u password’ for authentication query

emq_auth_mongo Plugin

Support mongodb Cluster, Replica Set


Add ‘Build on Windows’ chapter

Version 2.2-beta.2

Release Date: 2017-05-20

Bugfix and Enhancements

Add a ‘websocket_protocol_header’ option to handle WebSocket connection from WeChat (emqttd#1060)

Assign username and password to MQTT-SN’s CONNECT message (emqttd#1041)

Allow for Content-Type:application/json in HTTP Publish API (emqttd#1045)

emqttd_http.erl:data conversion (emqttd#1059)

Seperate emq_sn from emqttd (emq-sn#24)

Check St0’s type, making it easier to debug crash problems (emq-lua-hook#6)

Fix error: load xxx.lua (emq-lua-hook#8)

Leave luerl alone as a rebar project (emq-lue-hook#9)

Display websocket data in reverse order (emq-dashboard#118)

priv/www/assets/js/dashboard.js:Fixed a typo (emq-dashboard#118)


Update README of emq-auth-pgsql: add the ‘ssl_opts’ configuration (emq-auth-pgsql#56)

Update README of emq-auth-mysql: fix the ‘passwd_hash’ typo (emq-auth-mysql#54)

Update README of emq-auth-mongo: change ‘aclquery’ to ‘acl_query’ (emq-auth-mongo#63)

Elixir Plugin

Add a new plugin emq-elixir-plugin to support Elixir language.

Version 2.2-beta.1

Release Date: 2017-05-05

EMQ 2.2-beta.1 is now available. Many new features including Web Hook, Lua Hook and Proxy Protocol have been released in this version.

MQTT Listeners

Support to configure multiple MQTT TCP/SSL listeners for one EMQ node. For example:

-- External TCP 1883 --> |     |
                         | EMQ | -- Internal TCP 2883 --> Service
-- External SSL 8883-->  |     |

Configure a listener in etc/emq.conf:


listener.tcp.${name}.acceptors = 16

listener.tcp.${name}.max_clients = 102400

Proxy Protocol V1/2

The EMQ cluster is usually deployed behind a Load Balancer, such as HAProxy or NGINX:

              |   |
              | L | --TCP 1883--> EMQ
--SSL 8883--> |   |                |
              | B | --TCP 1883--> EMQ
              |   |

The LB can pass the source IP, port of the TCP connection on to EMQ cluster by Proxy Protocol.

Enable Proxy Protocol support for MQTT Listener:

## Proxy Protocol V1/2
## listener.tcp.${name}.proxy_protocol = on
## listener.tcp.${name}.proxy_protocol_timeout = 3s

Web Hook Plugin

The Web Hook plugin emq-web-hook can trigger a webhook callback when a MQTT client connected to or disconnected from the broker, a MQTT message is published or acked.

Lua Hook Plugin

The Lua Hook plugin emq-lua-hook make it possible to extend the broker and write business logic with Lua script.

Improve the Auth/ACL Chain

We improved the Auth/ACL chain design in 2.2 release. The Auth request will be forwarded to next auth module if it is ignored by the current auth module:

           --------------           -------------           --------------
Client --> | Redis Auth | -ignore-> | HTTP Auth | -ignore-> | MySQL Auth |
           --------------           -------------           --------------
                 |                       |                       |
                \|/                     \|/                     \|/
           allow | deny            allow | deny            allow | deny

Support bcrypt password hash

Enable the bcrypt password hash in auth module, for example:

auth.redis.password_hash = bcrypt

API Breaking Change

etc/emq.conf: ‘mqtt.queue.*’ changed to ‘mqtt.mqueue.*’


Support ‘Unsubscribe’ action on WebSocket Page.

Version 2.1.2

Release Date: 2017-04-21

Fix emqttd_ctl sessions list CLI

Newline character in emq.conf causing error;(emqttd#1000)

Fix crash caused by duplicated PUBREC packet (emqttd#1004)

Unload the ‘session.created’ and ‘session.teminated’ hooks (emq-plugin-template)

Version 2.1.1

Release Date: 2017-04-14

Localhost:8083/status returns 404 when AWS LB check the health of EMQ (emqttd#984)

Https listener not working in 2.1.0 as in 2.0.7 (emq-dashboard#105)

Fix mqtt-sn Gateway not working (emq-sn#12)

Upgrade emq-sn Plugin (emq-sn#11)

Upgrade emq-coap Plugin (emq-coap#21)

Version 2.1.0

Release Date: 2017-04-07

The stable release of 2.1 version.

Trouble with auth.mysql.acl_query (emq-auth-mysql#38)

Filter the empty fields in ACL table (emq-auth-mysql#39)

Version 2.1.0-rc.2

Release Date: 2017-03-31

Support pbkdf2 hash (emq-auth-mongo#46)

Kickout the conflict WebSocket connection (emqttd#963)

Correct licence in app.src (emqttd#958)

SSL options to connect to pgsql (emq-auth-pgsql#41)

Version 2.1.0-rc.1

Release Date: 2017-03-24

EMQ fails to start if run under a different linux user than that which first ran it (emqttd#842)

Depend on emqtt/pbkdf2 to fix the building errors of Travis CI (emqttd#957)

Depend on goldrush and emqtt/pbkdf2 to resolve the building errors (emqttd#956)

Fix ‘rebar command not found’ (emq-relx#33)

Compile error in v2.1.0-beta.2 (emq-relx#32)

Support salt with passwords (emq-auth-mongo#11)

Change the default storage_type to ‘ram’ (emq-retainer#13)

Version 2.1.0-beta.2

Release Date: 2017-03-13

Cannot find AwaitingAck (emqttd#597)

EMQ V2.1 crash when public with QoS = 2 (emqttd#919)

Support pbkdf2 hash (emqttd#940)

Add src/ to be compatible with rebar3 (emqttd#920)

Add more test cases (emqttd#944)

CRASH REPORT Process <0.1498.0> with 0 neighbours crashed with reason: {ssl_error,{tls_alert,”certificate unknown”}} in esockd_connection:upgrade (emqttd#915)

auth.redis.password_hash = plain by default (emq-auth-redis#20)

Version 2.1.0-beta.1

Release Date: 2017-02-24

EMQ v2.1.0-beta.1 is now available.


EMQ 2.1+ Requires Erlang/OTP R19+ to build.

Since 2.1.0 release, we will tag EMQ versions accoding to the Semantic Versioning 2.0.0 principles. And we will release EMQ versions monthly, odd number releases for bugfix and optimization, and even number releases for bugfix and new features.

Tuning GC

  1. All the WebSocket, Client, Session processes will hiberante and GC after a period of idle time.
  2. Add ‘mqtt.conn.force_gc_count’ configuration to force the Client, Session processes to GC when high message throughput.
  3. Tune the ‘fullsweep_after’ option of WebSocket, Client, Session processes.

Hooks API

Hooks module now support to register the same function with different tags.


emqttd#916: Add ‘mqtt_msg_from()’ type

emq-auth-http#15: ACL endpoint isnt called

Version 2.1-beta

Version 2.1-beta

Release Date: 2017-02-18

EMQ v2.1-beta is now available. We improved the design of Session/Inflight and use one timer to redeliver the inflight QoS1/2 messages, and improved the GC mechanism of MQTT connection process to reduce CPU usage at the high rate of messages.

Per Client, Session Statistics

Support Per Client, Session Statistics. Enable by configuration in etc/emq.conf:

mqtt.client.enable_stats = 60s

mqtt.session.enable_stats = 60s

Add ‘missed’ Metrics

The ‘missed’ metrics will be increased when EMQ broker received PUBACK, PUBREC, PUBREL, PUBCOMP packets from clients, but missing in inflight window:





Integrate Syslog

Output EMQ log to syslog:

## Syslog. Enum: on, off
log.syslog = on

##  syslog level. Enum: debug, info, notice, warning, error, critical, alert, emergency
log.syslog.level = error

Upgrade QoS

Support to upgrade QoS accoding to the subscription:

mqtt.session.upgrade_qos = on

Add ‘acl reload’ CLI

Reload acl.conf without restarting emqttd service (#885)

etc/emq.conf Changes

  1. Rename mqtt.client_idle_timeout to mqtt.client.idle_timeout
  2. Add mqtt.client.enable_stats
  3. Add mqtt.session.upgrade_qos
  4. Delete mqtt.session.collect_interval
  5. Add mqtt.session.enable_stats
  6. Rename mqtt.session.expired_after to mqtt.session.expiry_interval

Merge modules to emq_modules

Merge the emq_mod_presence, emq_mod_subscription, emq_mod_rewrite into emq_modules

Rename emq_mod_retainer to emq_retainer project

Dashboard Plugin

Overview page: Add ‘missed’ metrics Client page: Add ‘SendMsg’, ‘RecvMsg’ Fields Session page: Add DeliverMsg, EnqueueMsg Fields

recon Plugin

Change the datatype of ‘recon.gc_interval’ to duration

reloader Plugin

Change the datatype of ‘reloader.interval’ to duration

Version 2.0.7

Release Date: 2017-01-20

The Last Maintenance Release for EMQ 2.0, and support to build RPM/DEB Packages.

Create the emq-package project:

emq-auth-http#9: Update the priv/emq_auth_http.schema, cuttlefish:unset() if no super_req/acl_req config exists

emq-auth-mongo#31: cuttlefish:unset() if no ACL/super config exists

emq-dashboard#91: Fix the exception caused by binary payload

emq-relx#21: Improve the binemqttd.cmd batch script for windows platform

emqttd#873: Documentation: installing-from-source

emqttd#870: Documentation: The word in Documents is wrong

emqttd#864: Hook ‘client.unsubscribe’ need to handle ‘stop’

emqttd#856: Support variables in etc/emq.conf: {{ runner_etc_dir }}, {{ runner_etc_dir }}, {{ runner_data_dir }}

Version 2.0.6

Release Date: 2017-01-08

Upgrade the esockd library to v4.1.1

esockd#41: Fast close the TCP socket if ssl:ssl_accept failed

emq-relx#15: The EMQ 2.0 broker cannot run on Windows.

emq-auth-mongo#31: Mongodb ACL Cannot work?

Version 2.0.5

Release Date: 2016-12-24

emq-auth-http#9: Disable ACL support

emq-auth-mongo#29: Disable ACL support

emq-auth-mongo#30: {datatype, flag}

Version 2.0.4

Release Date: 2016-12-16

emqttd#822: Test cases for SSL connections

emqttd#818: trap_exit to link WebSocket process

emqttd#799: Can’t publish via HTTPS

Version 2.0.3

Release Date: 2016-12-12

emqttd#796: Unable to forbidden tcp lisener

emqttd#814: Cannot remove a ‘DOWN’ node from the cluster

emqttd#813: Change parameters order

emqttd#795: Fix metrics of websocket connections

emq-dashboard#88: Rename the default topic from “/World” to “world”

emq-dashboard#86: Lookup all online clients

emq-dashboard#85: Comment the default listener port

emq-mod-retainer#3: Retained messages get lost after EMQTT broker restart.

Version 2.0.2

Release Date: 2016-12-05

emqttd#787: Stop plugins before the broker stopped, clean routes when a node down

emqttd#790: Unable to start emqttd service if username/password contains special characters

emq-auth-clientid#4: Improve the configuration of emq_auth_clientid.conf to resolve emqttd#790

emq-auth-username#4: Improve the configuration of emq_auth_username.conf to resolve emqttd#790

Version 2.0.1

Release Date: 2016-11-30

emqttd#781: Update README for EMQ 2.0

emq_dashboard#84: Show the Cluster Status of Node

emq_dashboard#79: disc_copies to store mqtt_admin table

emq_auth_clientid: disc_copies to store mqtt_auth_clientid table

emq_auth_username: disc_copies to store mqtt_auth_username table

emq_mod_subscription#3: Remove emq_mod_subscription table and module.subscription.backend config

emq_plugin_template#5: Unregister Auth/ACL modules when the plugin unloaded

Version 2.0 “West of West Lake”

Release Date: 2016-11-24

Release Name: West of West Lake

The EMQ Version 2.0, named “West of West Lake”, has been released with a lot of improvements and enhancements, and is ready to deploy in production now.

  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.

Shared Subscription

Shared Subscription supports Load balancing to distribute MQTT messages between multiple subscribers in the same group:

                            |       | --Msg1--> Subscriber1
Publisher--Msg1,Msg2,Msg3-->|  EMQ  | --Msg2--> Subscriber2
                            |       | --Msg3--> Subscriber3

Create a shared subscription with $queue/ or $share/<group>/ prefix:

Prefix Examples
$queue/ mosquitto_sub -t ‘$queue/topic
$share/<group>/ mosquitto_sub -t ‘$share/group/topic

Local Subscription

The Local Subscription will not create global routes on clustered nodes, and only dispatch MQTT messages on local node.

Usage: subscribe a topic with $local/ prefix. and relx

The EMQ 2.0 adopts and relx tools to build the whole projects on Linux, Unix and Windows.

CoAP Support

The EMQ 2.0 supports CoAP(RFC7252) protocol/gateway now, and supports communication between CoAP, MQTT-SN and MQTT clients.

CoAP Protocol Plugin:

MQTT-SN Support

The EMQ 2.0 now supports MQTT-SN protocol/gateway.

MQTT-SN Plugin:

New Configuration File

The release integrated with cuttlefish library, and adopted a more user-friendly k = v syntax for the new configuration file:

## Node name = emqttd@
## Max ClientId Length Allowed.
mqtt.max_clientid_len = 1024

The new configuration files will be preprocessed and translated to an Erlang app.config before the EMQ broker started:

----------------------                                          2.0/schema/*.schema      -------------------
| etc/emq.conf       |                   -----------------              \|/              | data/app.config |
|       +            | --> mergeconf --> | data/app.conf | -->  cuttlefish generate  --> |                 |
| etc/plugins/*.conf |                   -----------------                               | data/vm.args    |
----------------------                                                                   -------------------

OS Environment Variables

EMQ_NODE_NAME Erlang node name
EMQ_NODE_COOKIE Cookie for distributed erlang node
EMQ_MAX_PORTS Maximum number of opened sockets
EMQ_TCP_PORT MQTT TCP Listener Port, Default: 1883
EMQ_SSL_PORT MQTT SSL Listener Port, Default: 8883
EMQ_HTTP_PORT HTTP/WebSocket Port, Default: 8083
EMQ_HTTPS_PORT HTTPS/WebSocket Port, Default: 8084

Docker Image

We released an official Docker Image for EMQ 2.0. The open source project for Dockerfile:

Full Support for Windows

The EMQ 2.0 fully supports Windows platform. You can run ‘emqttd_ctl’ command and cluster two nodes on Windows now.

Bugfix and Enhancements

#764: add mqtt.cache_acl option

#667: Configuring emqttd from environment variables

#722: mqtt/superuser calls two times emqtt_auth_http

#754: “-heart” option for EMQ 2.0

#741: emq_auth_redis cannot use hostname as server address


Plugin Description
emq_dashboard Web Dashboard
emq_auth_clientid ClientId Auth Plugin
emq_auth_username Username/Password Auth Plugin
emq_auth_ldap LDAP Auth
emq_auth_http HTTP Auth/ACL Plugin
emq_auth_mysql MySQL Auth/ACL Plugin
emq_auth_pgsql PostgreSQL Auth/ACL Plugin
emq_auth_redis Redis Auth/ACL Plugin
emq_auth_mongo MongoDB Auth/ACL Plugin
emq_mod_presence Presence Module
emq_mod_retainer Retainer Module
emq_mod_rewrite Topic Rewrite Module
emq_mod_subscription Subscription Module
emq_coap CoAP Protocol Plugin
emq_sn MQTT-SN Protocol Plugin
emq_stomp STOMP Protocol Plugin
emq_sockjs STOMP over SockJS Plugin
emq_recon Recon Plugin
emq_reloader Reloader Plugin
emq_plugin_template Template Plugin

Version 2.0-rc.3

Release Date: 2016-11-01

  1. Change the three modules(Presence, Retainer, Subscription) to standalone plugins:
emq_mod_retainer Retained Message Storage
emq_mod_presence Publish presence message to $SYS topics when client connected or disconnected
emq_mod_subscription Subscribe topics automatically when client connected
  1. Update the SSL certificates under the etc/certs/ folder.
  2. Bugfix: Fixed a typo (#716)
  3. Bugfix: emqttd_http can not use emq_auth_http? #739
  4. Bugfix: emq_auth_redis cannot use hostname as server address (#741)
  5. Upgrade Redis, MySQL, Postgre and MongoDB plugins to support hostname.

Version 2.0-rc.2

Release Date: 2016-10-19

  1. A more user-friendly configuration for the EMQ broker. Integrate with cuttlefish library and adopt K = V syntax: = emqttd@
    mqtt.listener.tcp = 1883
  2. Support OS Environments:

  3. Refactor all the modules and plugins, and adopt new configuration syntax.

TODO: issues closed.

Version 2.0-rc.1

Release Date: 2016-10-03

  1. mqtt/superuser POST called two times in emqtt_auth_http (#696)

  2. Close MQTT TCP connection if authentication failed (#707)

  3. Improve the plugin management. Developer don’t need to add plugin’s config to rel/sys.config

  4. Add BUILD_DEPS in the plugin’s Makefile:

    BUILD_DEPS = emqttd
    dep_emqttd = git emq20
  5. Improve the design of Redis ACL.

Version 2.0-beta.3

Release Date: 2016-09-18

New Features

Shared Suscriptions (#639, #416):

mosquitto_sub -t '$queue/topic'
mosquitto_sub -t '$share/group/topic'

Local Subscriptions that will not create global routes:

mosquitto_sub -t '$local/topic'


Error on Loading emqttd_auth_http (#691)

Remove ‘emqttd’ application from dependencies (emqttd_coap PR#3)

Version 2.0-beta.2

Release Date: 2016-09-10

CoAP Support

Release an experimental CoAP Gateway:

API Breaking Changes

‘$u’, ‘$c’ variables in emqttd.conf and modules/acl.conf changed to ‘%u’, ‘%c’

Improve the design of mqtt retained message, replace emqttd_retainer with emqttd_mod_retainer.

Add ‘session.subscribed’, ‘session.unsubscribed’ hooks, remove ‘client.subscribe.after’ hook

Tab ‘retained_message’ -> ‘mqtt_retained’


[2.0 beta1] FORMAT ERROR: “~s PUBLISH to ~s: ~p” (PR #671)

Fixing issues in cluster mode. (PR #681)

Fixing issues with unsubscribe hook (PR #673)

Version 2.0-beta.1

Release Date: 2016-08-30

Release Name: West of West Lake

EMQ - Shortened Project Name

Adopt a shortened project name: EMQ(Erlang/Enterprise/Elastic MQTT Broker), E means Erlang/OTP, Enterprise and Elastic.

Improve the Release Management

In order to iterate the project fast, we will adopt a new release management strategy since 2.0. There will be two or three ‘Preview Release’ named beta1, beta2 or beta3, and then one or two ‘Release Candidate’ named rc1, rc2 before a Major version is production ready.

Seperate Rel from Application

We split the emqttd 1.x project into two projects since 2.0-beta1 release to resolve the plugins’ dependency issue.

A new project named emqttd-relx is created and responsible for buiding the emqttd application and the plugins:

git clone

cd emqttd-relx && make

cd _rel/emqttd && ./bin/emqttd console and relx

The rebar which is used in 1.x release is replaced by and relx tools since 2.0-beta1 release.

You can check the ‘Makefile’ and ‘relx.config’ in the release project of the borker: emqttd-relx .

Improve Git Branch Management

stable 1.x Stable Branch
master 2.x Master Branch
emq10 1.x Developement Branch
emq20 2.x Development Branch
emq30 3.x Development Branch
issue#{id} BugFix Branch

New Config Syntax

Since 2.0-beta1 release the configuration file of the broker and plugins adopt a new syntax like rebar.config and relx.config:

etc/emqttd.conf for example:

%% Max ClientId Length Allowed.
{mqtt_max_clientid_len, 512}.

%% Max Packet Size Allowed, 64K by default.
{mqtt_max_packet_size, 65536}.

%% Client Idle Timeout.
{mqtt_client_idle_timeout, 30}. % Second

MQTT-SN Protocol Plugin

The MQTT-SN Protocol Plugin emqttd_sn has been ready in 2.0-beta1 release. The default UDP port of MQTT-SN is 1884.

Load the plugin:

./bin/emqttd_ctl plugins load emqttd_sn

Improve the PubSub Design


Improve the Plugin Management

The plugin of EMQ 2.0 broker is a normal erlang application which depends on and extends ‘emqttd’. You can create a standalone plugin application project, and add it to emqttd-relx Makefile as a DEP.

All the plugins’ config files will be copied to emqttd/etc/plugins/ folder when making emqttd brinary packages in emqttd-relx project:

▾ emqttd/
  ▾ etc/
    ▸ modules/
    ▾ plugins/

EMQ 2.0 Documentation


Version 1.1.3

Release Date: 2016-08-19

Support ‘./bin/emqttd_ctl users list’ CLI (#621)

Cannot publish payloads with a size of the order 64K using WebSockets (#643)

Optimize the procedures that retrieve the Broker version and Borker description in the tick timer (PR#627)

Fix SSL certfile, keyfile config (#651)

Version 1.1.2

Version 1.1.2

Release Date: 2016-06-30

Upgrade mysql-otp driver to 1.2.0 (#564, #523, #586, #596)

Fix WebSocket Client Leak (PR #612) using paho java client (#551)

Send message from paho java client to javascript client (#552)

Compatible with the Qos0 PUBREL packet (#575)

Empty clientId with non-clean session accepted (#599)

Update docs to fix typos (#601, #607)

Version 1.1.1

Release Date: 2016-06-04

Compatible with the Qos0 PUBREL packet (#575)

phpMqtt Client Compatibility (#572) using paho java client (#551)

Version 1.1

Release Date: 2016-06-01


Upgrade eSockd library to 4.0 and Support IPv6

Support to listen on specific IP Address:

{mqtt, {"", 1883}, [

Add MongoDB, HTTP Authentication/ACL Plugins

Upgrade MySQL, PostgreSQL, Redis Plugins to support superuser authentication and avoid SQL Injection


Allow human-friendly IP addresses (PR#395)

File operation error: emfile (#445)

emqttd_plugin_mongo not found in emqttd (#489)

emqttd_plugin_mongo Error While Loading in emqttd (#505)

Feature request: HTTP Authentication (#541)

Compatible with the Qos0 PUBREL packet (#575)


Bugfix: function_clause exception occurs when registering a duplicated authentication module (#542)

Bugfix: ./emqttd_top msg_q result: {“init terminating in do_boot”,{undef,[{etop,start,[],[]},{init,start_it,1,[]},{init,start_em,1,[]}]}} (#557)


111 common test cases.

Dashboard Plugin

WebSocket Page: Support ‘Clean Session’, Qos, Retained parameters (emqttd_dashboard#52)

Upgrade eSockd library to 4.0, Show OTP Release on Overview Page (emqttd_dashboard#61)

Changing dashboard credentials for username authentication (emqttd_dashboard#56)

Add ‘./bin/emqttd_ctl admins’ CLI, support to add/delete admins

HTTP Auth Plugin

Authentication/ACL by HTTP API:

MongoDB Plugin

Upgrade Erlang MongoDB driver to v1.0.0

Support superuser authentication

Support ACL (emqttd_plugin_mongo#3)

MySQL Plugin

Support superuser authentication

Use parameterized query to avoid SQL Injection

Postgre Plugin

Support superuser authentication

Use parameterized query to avoid SQL Injection

Redis Plugin

Support superuser authentication

Support ClientId authentication by ‘%c’ variable

Reloader Plugin

Reload modified modules during development automatically.

Version 1.0.3

Release Date: 2016-05-23

eSockd 3.2

MochiWeb 4.0.1

Version 1.0.2

Release Date: 2016-05-04

Issue#534 - ‘./bin/emqttd_ctl vm’ - add ‘port/count’, ‘port/limit’ statistics

Issue#535 - emqttd_client should be terminated properly even if exception happened when sending data

PR#519 - The erlang ‘-name’ requires the fully qualified host name

emqttd_reloader plugin - help reload modified modules during development.

Version 1.0.1

Release Date: 2016-04-16

PR#515 - Fix ‘$queue’ pubsub, add ‘pubsub_queue’ test and update docs

Version 1.0 (The Seven Mile Journey)

Release Date: 2016-04-13

Release Name: The Seven Mile Journey

We finally released Version 1.0 (The Seven Mile Journey) with full documentation after two years’ development and more than fifty iterations.

The emqttd 1.0 implements a fully-featured, scalable, distributed and extensible open-source MQTT broker for IoT, M2M and Mobile applications:

  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

Bugfix and Enhancements

Possible race condition using emqttd_cm (#486)

Improve the design of retained message expiration (#503)

Do not expire the retained messages from $SYS/# topics (#500)


Thank Ericsson for the Great Erlang/OTP Platform (!

Contributors on GitHub: @callbay @lsxredrain @hejin1026 @desoulter @turtleDeng @Hades32 @huangdan @phanimahesh @dvliman @Prots @joaohf

Partners: EACG (

Favorite Band: The Seven Mile Journey (

Version 0.17.1-beta

Release Date: 2016-03-22


Time unit of session ‘expired_after’ changed to minute. (#479)


Code Review and improve the design of Dashboard.

Version 0.17.0-beta

Release Date: 2016-03-15


Installation and Configuration Guide released on

Improve and Consolidate the design of Hook, Server, PubSub and Router

Upgrade the [Web Dashboard]( to support pagination

Bridge emqttd broker to another emqttd broker & emqttd to mosquitto bridge (#438)


emqttd_ctl: better error message (#450)

./bin/emqttd_ctl: add ‘routes’ command:

routes list             # List all routes
routes show <Topic>     # Show a route

Add ‘backend_subscription’ table and support static subscriptions (emqttd_backend)

Add ‘retained_message’ table and refactor emqttd_retainer module (emqttd_backend)

A New Hook and Callback Design (emqttd_hook)

Add PubSub, Hooks APIs to emqttd module (emqttd)

Move start_listeners/0, stop_listeners/0 APIs to emqttd_app module (emqttd_app)


Add 100+ common test cases.


Upgrade Dashboard, Redis, Stomp and Template Plugins

Version 0.16.0-beta

Release Date: 2016-02-16


Licensed under the Apache License, Version 2.0 Now.

Improve the design of cluster, support to join or leave the cluster (#449):

$ ./bin/emqttd_ctl cluster
cluster join <Node>                     #Join the cluster
cluster leave                           #Leave the cluster
cluster remove <Node>                   #Remove the node from cluster
cluster status                          #Cluster status

Improve the design of Trie and Route, only the wildcard topics stored in Trie.

Common Test to replace EUnit.


mqtt_message record: add ‘sender’ field (#440)

refactor the emqttd, emqttd_time, emqttd_opts, emqttd_node modules.


noproc error when call to gen_server2:call(false, {add_route,Topic,<0.685.0>}, infinity) (#446)


Changed the license of all plugins.

Version 0.15.0-beta

Release Date: 2016-01-31


Optimize for Push Application, 500K+ Subscribers to a Topic.

Optimization for Route ETS insertion (#427)

Priority Message Queue for Persistent Session (#432)

Add Redis, MongoDB Plugins (#417)


Username/Password Authentication: Support to configure default users (#428)

Improve CLI Commands: pubsub, bridges, trace (#429)

emqttd_mod_subscription: fix client_connected/3

emqttd_auth_mod: add passwd_hash/2 function

priority_queue: add plen/2, out/2 functions


Fix dequeue/1 of emqttd_bridge…

Add emqttd:seed_now/0 function


emqttd_plubin_mysql: Changed mysql driver to mysql-otp

emqttd_plugin_pgsql: Integrate with ecpool

emqttd_plugin_redis: First release

emqttd_plugin_mongo: First release

Version 0.14.1-beta

Release Date: 2015-12-28

Bugfix: emqttd_ws_client.erl: Unexpected Info: {‘EXIT’,<0.27792.18>,{shutdown,destroy}} (#413)

Improve: fix spec errors found by dialyzer

Version 0.14.0-beta

Release Date: 2015-12-18


Scaling to 1.3 Million Concurrent MQTT Connections on a 12 Core, 32G CentOS server.

New PubSub, Router Design (#402). Prepare for scaling to 10 millions on one cluster.


Improve the gproc_pool usage with a general emqttd_pool_sup

Improve the design of emqttd_pubsub, add a new emqttd_router module

Improve the design of the whole supervisor tree

Route aging mechanism to remove the topics that have no subscriptions

Improve the dashboard, mysql, pgsql, stomp, sockjs plugins

Add ‘topics’, ‘subscriptions’ admin commands

Avoid using mnesia table index and mnesia:index_read API to lower CPU usage

Subscribe timeout exception (#366)

Long Delay on Multiple Topic Subscription (#365)

Subscriptions persistence (#344)

emqttd_ctl: ‘subscriptions’ command to force clients to subscribe some topics (#361)


emqttd_sm: spec of lookup_session/1 is not right BUG (#411)

Observer application should be removed from reltool.config for ‘wx’ app is not available (#410)


1.3 million concurrent MQTT connections on a 12 Core, 32G CentOS Server, consume about 15G Memory and 200% CPU.

Version 0.13.1-beta

Release Date: 2015-11-28

Bugfix: Plugin pathes error under windows (#387)

Improve: Too many error logs “[error] Session ….. Unexpected EXIT: client_pid=<0.14137.35>, exit_pid=<0.30829.22>, reason=nop…” (#383)

Improve: Define QOS0/1/2, Pooler Error (PR#382)

Improve: High CPU load when 400K unstable mobile connections (#377)

BugFix: emqttd_plugin_pgsql - error using same query with latest update plugin (pgsql#5)

Version 0.13.0-beta

Release Date: 2015-11-08


Rate Limiting based on [Token Bucket]( and [Leaky Bucket]( Algorithm

Upgrade eSockd and MochiWeb libraries to support Parameterized Connection Module

Improve emqttd_client to support fully asynchronous socket networking


Protocol Compliant - Session Present Flag (#163)

Compilation fails if repo is cloned with a different name (#348)

emqttd_client: replace gen_tcp:send with port_command (#358)

TCP sndbuf, recbuf, buffer tuning (#359)

emqttd_client.erl to handle ‘inet_async’, ‘inet_reply’ properly (#360)

Refator the [client/session management design](


Cannot kick transient client out when clientId collision (#357)

Fix the order of emqttd_app:start_server/1 (#367)

emqttd_session:subscribe/2 will crash (#374)


[benchmark for 0.13.0 release](

3.1G memory and 50+ CPU/core:

Connections: 250K
Subscribers: 250K
Topics:      50K
Qos1 Messages/Sec In:  4K
Qos1 Messages/Sec Out: 20K
Traffic In(bps):  12M+
Traffic Out(bps): 56M+

Version 0.12.3-beta

Release Date: 2015-10-22

Bugfix: emqttd_sysmon crasher for ‘undefined’ process_info (#350)

Bugfix: emqttd_client: catch parser exception (#353)

Version 0.12.2-beta

Release Date: 2015-10-16

Bugfix: Retained messages should not be expired if ‘broker.retained.expired_after = 0’ (#346)

Version 0.12.1-beta

Release Date: 2015-10-15

Highlight: Release for Bugfix and Code Refactor.

Feature: Retained message expiration (#182)

Improve: ‘$SYS/#’ publish will not match ‘#’ or ‘+/#’ (#68)

Improve: Add more metrics and ignore ‘$SYS/#’ publish (#266)

Improve: emqttd_sm should be optimized for clustered nodes may be crashed (#282)

Improve: Refactor emqttd_sysmon and suppress ‘monitor’ messages (#328)

Task: benchmark for 0.12.0 release (#225)

Benchmark: About 900K concurrent connections established on a 20Core, 32G CentOS server.

Version 0.12.0-beta

Release Date: 2015-10-08


Enhance the emqttd_ctl module to allow plugins to register new commands (#256)

Add [emqttd_recon plugin]( to debug/optimize the broker (#235)

Add ‘./bin/emqttd_ctl broker pubsub’ command to check the status of core pubsub processes

Add ‘./bin/emqttd_top’ command(like etop) to show the top ‘msg_q’, ‘reductions’, ‘memory’ or ‘runtime’ processes

‘rel/files/emqttd.config.production’ for production deployment(default)

‘rel/files/emqttd.config.development’ for development deployment


Qos1/2 messages will not be dropped under unstable mobile network (#264)

emqttd_session:subscribe/2, emqttd_session:unsubscribe/2 APIs should be asynchronous (#292)

etc/emqttd.config: ‘idle_timeout’ option to close the idle client(socket connected but no ‘CONNECT’ frame received)

etc/emqttd.config: ‘unack_retry_interval’ option for redelivering Qos1/2 messages

How to monitor large ‘message_queue_len’ (#283)


Behaviour emqttd_auth_mod is missing init callback (#318)


Write a new [benchmark tool]( to benchmark this release

Hw requirements - 5K users, 25-50 msgs/sec, QoS=1 (#209)

Supported Number of Connections Greatly Reduced When Clients are Subscribing (#324)

Version 0.11.0-beta

Release Date: 2015-09-25

Highlight: Rebar to manage plugin dependencies.

Highlight: [Stomp]( and [SockJS]( Plugins!

Improve: add rel/files/emqttd.config.development|production.

Improve: rel/reltool.config.script to release deps of plugin.

Improve: persist mnesia schema on slave nodes.

Improve: use timer:seconds/1 api.

Improve: The binary release will be compiled with R18.1 now.

Bugfix: issue#306 - emqttd_cm should unregister the duplicated client

Bugfix: issue#310 - usage of emqttd_ctl error: ‘session list’ should be ‘sessions list’

Bugfix: issue#311 - ‘./bin/emqttd_ctl sessions list’ error

Bugfix: issue#312 - unsubcribe will lead to crash if emqttd_plugin_template plugin loaded

Version 0.10.4-beta

Release Date: 2015-09-18

Optimize session management and upgrade eSockd library to 2.7.1

[Benchmark for 0.10.4 release](

Improve: issue#294 - [error] failed to start connection on - enotconn

Improve: issue#297 - How do I allow user with some pattern to access topic with some pattern?

Bugfix: issue#291 - “./bin/emqttd attach …” cannot work

Bugfix: issue#284 - Should not use erlang:list_to_atom/1 in emqttd_vm.erl

Version 0.10.3-beta

Release Date: 2015-08-30

Bugfix: issue#271 - add emqttd_ws_client:subscribe/2 function

Bugfix: issue#269 - bin/emqttd Syntax error on ubuntu

Improve: issue#265 - client under unstable mobile network generate a lot of logs

Version 0.10.2-beta

Release Date: 2015-08-26

Improve: issue#257 - After the node name changed, the broker cannot restart for mnesia schema error.

Version 0.10.1-beta

Release Date: 2015-08-25

Bugfix: issue#259 - when clustered the emqttd_dashboard port is close, and the ‘emqttd’ application cannot stop normally.

Feature: issue#262 - Add ‘https://host:8083/mqtt/status’ Page for health check

Version 0.10.0-beta

Release Date: 2015-08-20

[Web Dashboard]( and [MySQL](, [PostgreSQL]( Authentication/ACL Plugins!

Highlight: Web Dashboard to monitor Statistics, Metrics, Clients, Sessions and Topics of the broker.

Highlight: JSON/HTTP API to query all clients connected to broker.

Highlight: A new [Plugin Design]( and a [Template project]( for plugin development.

Highlight: Authentication/ACL with MySQL, PostreSQl databases (#194, #172)

Feature: Session Statistics including inflight_queue, message_queue, message_dropped, awaiting_rel, awaiting_ack, awaiting_comp (#213)

Feature: Cookie based authentication for MQTT over websocket connections (#231)

Feature: Get all clients connected to the broker (#228, #230, #148, #129)

Feature: “./bin/emqttd_ctl clients show ClientId” to query client status (#226)

Feature: “./bin/emqttd_ctl clients kick ClientId” to kick out a client

Feature: “./bin/emqttd_ctl sessions list” to show all sessions

Feature: “./bin/emqttd_ctl sessions show ClientId” to show a session

Feature: Erlang VM metrics monitor with Web Dashboard (#59)

Improve: Too many “inflight queue is full!” log when session is overloaded (#247)

Improve: There are two many “MQueue(~s) drop ~s” logs if the message queue of session is small (#244)

Improve: gen_server2(from RabbitMQ) to improve emqttd_session, emqttd_pubsub

Improve: Makefile to build plugins

Bugfix: emqttd_broker:unhook/2 cannot work (#238)

Bugfix: emqttd plugin cannot include_lib(“emqttd/include/emqttd.hrl”) (#233)

Bugfix: Too many ‘Session ~s cannot find PUBACK’ logs (#212)

Bugfix: emqttd_pooler cannot work

Version 0.9.3-alpha

Release Date: 2015-07-25

Wiki: [Bridge](

Improve: emqttd_protocol.hrl to define ‘QOS_I’

Improve: emqttd_pubsub to add subscribe/2 API

Improve: ./bin/emqttd_ctl to support new bridges command

Bugfix: issue #206 - Cannot bridge two nodes

Version 0.9.2-alpha

Release Date: 2015-07-18

Improve: issue #196 - Add New Hook ‘client.subscribe.after’

Version 0.9.1-alpha

Release Date: 2015-07-10

Bugfix: issue #189 - MQTT over WebSocket(SSL) cannot work?

Bugfix: issue #193 - ‘client.ack’ hook should be renamed to ‘message.acked’, and called by emqttd_broker:foreach_hooks

Version 0.9.0-alpha

Release Date: 2015-07-09

[Session, Queue, Inflight Window, Hooks, Global MessageId and More Protocol Compliant]( Now!

Feature: Session/Queue/Inflight Window Design (#145).

Feature: Support to resume a persistent session on other clustered node.

Feature: Support alarm management.

Feature: emqttd_guid to generate global unique message id.

Feature: Hooks for message pub/ack.

Feature: Protocol compliant - message ordering, timeout and retry.

Improve: Every client will start_link a session process, whether or not the client is persistent.

Improve: etc/emqttd.config to support more session, queue configuration.

Improve: issue #179 - Max offline message queue {max_queue, 100} meaning.

Improve: issue #180 - Should change project structure for other projects maybe depend on ‘emqttd’. Merge emqtt, emqttd apps.

Improve: issue #185 - PacketId and MessageId: the broker should generate global unique message id.

Improve: issue #187 - etc/emqttd.config to support https listener

Improve: issue #186 - emqttd_cm to store client details

Improve: issue #174 - add ‘from’ field to mqtt_message record.

Improve: issue #170 - $SYS Topics should support alarms.

Improve: issue #169 - Add More [Hooks](

Improve: issue #167 - Inflight window to assure message ordering.

Improve: issue #166 - Message delivery timeout and retry.

Improve: issue #143 - Qos1, Qos2 PubSub message timeout.

Improve: issue #122 - Labeling message with unique id. emqttd_guid module to generate global unique msgid.

Improve: emqttd_bridge to support pending message queue, and fix the wrong Qos design.

Improve: mqtt_message record to add ‘msgid’, ‘from’ and ‘sys’ fields.

Change: Add emqttd_mqueue, emqttd_guid, emqttd_alarm modules.

Bugfix: issue #184 - emqttd_stats:setstats is not right.

Bugfix: Closed issues #181, #119.

Tests: fix the parser, acl test cases.

Version 0.8.6-beta

Release Date: 2015-06-17

Bugfix: issue #175 - publish Will message when websocket is closed without ‘DISCONNECT’ packet

Version 0.8.5-beta

Release Date: 2015-06-10

Bugfix: issue #53 - client will receive duplicate messages when overlapping subscription

Version 0.8.4-beta

Release Date: 2015-06-08

Bugfix: issue #165 - duplicated message when publish ‘retained’ message to persistent client

Version 0.8.3-beta

Release Date: 2015-06-05

Bugfix: issue #158 - should queue:in new message after old one dropped

Bugfix: issue #155 - emqtt_parser.erl: parse_topics/3 should reverse topics

Bugfix: issue #149 - Forget to merge plugins/emqttd_auth_mysql from ‘dev’ branch to ‘master’ in 0.8.x release

Version 0.8.2-alpha

Release Date: 2015-06-01

Bugfix: issue #147 - WebSocket client cannot subscribe queue ‘$Q/queue/${clientId}’

Bugfix: issue #146 - emqttd_auth_ldap: fill(Username, UserDn) is not right

Version 0.8.1-alpha

Release Date: 2015-05-28

Client [Presence]( Support and [$SYS Topics]($SYS-Topics) Redesigned!

Bugfix: issue #138 - when client disconnected normally, broker will not publish disconnected $SYS message

Bugfix: fix websocket url in emqttd/priv/www/websocket.html

Improve: etc/emqttd.config to allow websocket connections from any hosts

Improve: rel/reltool.config to exclude unnecessary apps.

Version 0.8.0-alpha

Release Date: 2015-05-25

[Hooks](, Modules and [Plugins]( to extend the broker Now!

Plugin: emqttd_auth_mysql - MySQL authentication plugin (issues #116, #120)

Plugin: emqttd_auth_ldap - LDAP authentication plugin

Feature: emqttd_broker to support Hooks API

Feature: issue #111 - Support ‘Forced Subscriptions’ by emqttd_mod_autosub module

Feature: issue #126 - Support ‘Rewrite rules’ by emqttd_mod_rewrite module

Improve: Support hooks, modules to extend the broker

Improve: issue #76 - dialyzer check

Improve: ‘Get Started’, ‘User Guide’, ‘Developer Guide’ Wiki

Improve: emqtt_topic to add join/1, feed_var/3, is_queue/1

Improve: emqttd_pooler to execute common tasks

Improve: add emqttd_sm_sup module, and use ‘hash’ gproc_pool to manage sessions

Tests: add more test cases for ‘emqttd’ app

Version 0.7.1-alpha

Release Date: 2015-05-04

Add doc/design/* and merge doc/* to github Wiki

Bugfix: issue #121 - emqttd cluster issuse

Bugfix: issue #123 - emqttd:unload_all_plugins/0 cannot unload any plugin

Bugfix: fix errors found by dialyzer

Version 0.7.0-alpha

Release Date: 2015-05-02

[MQTT over WebSocket(SSL)]( Now!

[Plugin Achitecture]( based on OTP application

[Trace MQTT Packets or Messages]( to log files

Feature: issue #40, #115 - WebSocket/SSL Support

Feature: issue #49, #105 - Plugin Architecture Support

Feature: issue #93 - Trace API Design

Improve: issue #109 - emqttd_broker should add subscribe, notify API

Improve: update to add ‘Goals’, ‘Contributors’ chapters

Change: rename etc/app.config to etc/emqttd.config

Change: etc/emqttd.config changed

Bugfix: critical issue #54 - error when resume session!

Bugfix: issue #118 - error report when UNSUBSCRIBE with no topics

Bugfix: issue #117 - sys_interval = 0 config cannot work

Bugfix: issue #112 - Makefile to support build plugins

Bugfix: issue #96 - “make clean” cannot work

Version 0.6.2-alpha

Release Date: 2015-04-24

Bugfix: critical issue #54, #104, #106 - error when resume session

Improve: add emqttd_cm_sup module, and use ‘hash’ gproc_pool to register/unregister client ids

Improve: kick old client out when session is duplicated.

Improve: move mnesia dir config from etc/app.config to etc/vm.args

Version 0.6.1-alpha

Release Date: 2015-04-20

Integrate with [gproc library]( to support pool

Feature: issues#91 - should use worker_pool to handle some async work?

Feature: issues#95 - Topic filters in ACL rule should support ‘eq’ tag

Improve: issues#84 - emqttd_pubsub is redesigned again to protect mnesia transaction

Improve: issues#74 - ACL Support and update [ACL Design Wiki](

Version 0.6.0-alpha

Release Date: 2015-04-17

ACL Support Now: [ACL-Design Wiki](

Authentication with username, clientid Now: [Authentication Wiki](

Seperate common MQTT library to ‘emqtt’ application

Redesign message pubsub, route and retain modules

Redesign mnesia database cluster

Feature: issues#47 - authentication, authorization support

Feature: issues#92 - merge emqttd_acl and emqttd_auth to emqttd_access_control

Feature: emqttd_acl_mod, emqttd_auth_mod behaviour to extend ACL, authentication

Feature: issues#85 - lager:info to log subscribe, unsubscribe actions

Feature: issues#77 - authentication with clientid, ipaddress

Improve: issues#90 - fix lager_file_backend log format, and rotate 10 log files

Improve: issues#88 - use ‘-mneisa_create’, ‘-mnesia_replicate’ attributes to init mneisa

Improve: issues#87 - record mqtt_user and mqtt_client is duplicated

Improve: issues#81 - redesign nodes cluster to support disc_copies mnesia tables

Improve: issues#80 - redesign emqttd_cm to handle more concurrent connections

Improve: issues#70 - how to handle connection flood? Now could support 2K+ CONNECT/sec

Change: redesign mnesia tables: message, topic, subscriber, trie, trie_node

Bugfix: issues#83 - emqttd_broker stats cannot work

Bugfix: issues#75 - careless about function name when emqttd_pubsub handle getstats message

Version 0.5.5-beta

Release Date: 2015-04-09

Bugfix: issue #75 - careless about function name when emqttd_pubsub handle getstats message.

Bugfix: issue #79 - cannot find topic_subscriber table after cluster with other nodes.

Version 0.5.4-alpha

Release Date: 2015-03-22

Benchmark this release on a ubuntu/14.04 server with 8 cores, 32G memory from

200K Connections,
30K Messages/Sec,
20Mbps In/Out Traffic,
200K Topics,
200K Subscribers,

Consumed 7G memory, 40% CPU/core

Benchmark code:

Change: rewrite emqttd_pubsub to handle more concurrent subscribe requests.

Change: ./bin/emqttd_ctl add ‘stats’, ‘metrics’ commands.

Bugfix: issue #71, #72

Version 0.5.3-alpha

Release Date: 2015-03-19

Bugfix: issues#72 - emqttd_cm, emqtt_sm ets:match_delete/2 with wrong pattern

Version 0.5.2-alpha

Release Date: 2015-03-18

Change: upgrade esockd to 2.1.0-alpha, do not tune socket buffer for mqtt connection.

Version 0.5.1-alpha

Release Date: 2015-03-13

Change: upgrade esockd to v1.2.0-beta, rename ‘acceptor_pool’ to ‘acceptors’

Version 0.5.0-alpha

Release Date: 2015-03-12

RENAME ‘emqtt’ to ‘emqttd’!

Support [Broker Bridge]( Now!

Change: rename project from ‘emqtt’ to ‘emqttd’

Change: lager:debug to dump RECV/SENT packets

Feature: emqttd_bridge, emqttd_bridge_sup to support broker bridge

Feature: emqtt_event to publish client connected/disconnected message to $SYS topics

Feature: ./bin/emqttd_ctl add more commands: listeners, broker, bridges, start_bridge, stop_bridge…

Feature: issue#57 - support to configure max packet size

Feature: issue#68 - if sys_interval = 0, emqttd_broker will not publish messages to $SYS/brokers/#

Bugfix: issue#67 - subscribe ‘#’ to receive all messages

Bugfix: issue#64 - emqtt_app start/2: should wait_for_databases

Test: emqttd_topic_tests add more ‘_match_test’

Version 0.4.0-alpha

Release Date: 2015-03-10

Support [$SYS Topics of Broker]($SYS-Topics-of-Broker) Now!

Feature: emqtt_broker to publish version, uptime, datetime to $SYS/brokers/# topics

Feature: emqtt_broker to publish count of clients, sessions, suscribers to $SYS/brokers/# topics

Feature: emqtt_metrics to publish bytes, packets, messages metrics to $SYS/brokers/# topics

Feature: add include/emqtt_systop.hrl

Change: emqtt_cm to count current clients

Change: emqtt_sm to count current sessions

Change: emqtt_pubsub to count current topics and suscribers

Change: emqtt_pubsub to add create/1 API

Change: emqtt_pubsub dispatch/2 to return number of subscribers

Change: emqtt_pubsub to count ‘dropped’ messages

Change: emqtt_opts to add merge/2 function

Test: add emqtt_serialiser_tests.erl

Version 0.3.4-beta

Release Date: 2015-03-08

Bugfix: emqtt_serialiser.erl cannot serialise UNSUBACK packets

Version 0.3.3-beta

Release Date: 2015-03-07

Bugfix: emqtt_serialiser.erl cannot serialise PINGRESP issue#60

Version 0.3.2-beta

Release Date: 2015-03-05

Improve: merge emqttc serialiser, parser, packet

Add: emqtt_opts to merge socket options

Version 0.3.1-beta

Release Date: 2015-03-02

Feature: SSL Socket Support

Feature: issue#44 HTTP API should add Qos parameter

Bugfix: issue#52 emqtt_session crash

Bugfix: issue#53 sslsocket keepalive error

Upgrade: esockd to v0.2.0

Upgrade: mochiweb to v3.0.0

Version 0.3.0-beta

Release Date: 2015-01-19

Feature: HTTP POST API to support ‘qos’, ‘retain’ parameters

Feature: $SYS system topics support

Change: Rewrite emqtt_topic.erl, use ‘’, ‘#’, ‘+’ to replace <<”“>>, <<”#”>>, <<”+”>>

Change: fix emqtt_pubsub.erl to match ‘#’, ‘+’

Tests: emqtt_topic_tests.erl add more test cases

Version 0.3.0-alpha

Release Date: 2015-01-08

NOTICE: Full MQTT 3.1.1 support now!

Feature: Passed org.eclipse.paho.mqtt.testing/interoperability tests

Feature: Qos0, Qos1 and Qos2 publish and suscribe

Feature: session(clean_sess=false) management and offline messages

Feature: redeliver awaiting puback/pubrec messages(doc: Chapter 4.4)

Feature: retain messages, add emqtt_server module

Feature: MQTT 3.1.1 null client_id support

Bugfix: keepalive timeout to send will message

Improve: overlapping subscription support

Improve: add emqtt_packet:dump to dump packets

Test: passed org.eclipse.paho.mqtt.testing/interoperability

Test: simple cluster test

Closed Issues: #22, #24, #27, #28, #29, #30, #31, #32, #33, #34, #36, #37, #38, #39, #41, #42, #43

Version 0.2.1-beta

Release Date: 2015-01-08

pull request 26: Use binaries for topic paths and fix wildcard topics

emqtt_pubsub.erl: fix wildcard topic match bug caused by binary topic in 0.2.0

Makefile: deps -> get-deps

rebar.config: fix mochiweb git url

tag emqtt release accoding to [Semantic Versioning](

max clientId length is 1024 now.

Version 0.2.0

Release Date: 2014-12-07

rewrite the project, integrate with esockd, mochiweb

support MQTT 3.1.1

support HTTP to publish message

Version 0.1.5

Release Date: 2013-01-05

Bugfix: remove QOS_1 match when handle PUBREL request

Bugfix: reverse word in emqtt_topic:words/1 function

Version 0.1.4

Release Date: 2013-01-04

Bugfix: fix “mosquitto_sub -q 2 ……” bug

Bugfix: fix keep alive bug

Version 0.1.3

Release Date: 2013-01-04

Feature: Support QOS2 PUBREC, PUBREL, PUBCOMP messages

Bugfix: fix emqtt_frame to encode/decoe PUBREC/PUBREL messages

Version 0.1.2

Release Date: 2012-12-27

Feature: release support like riak

Bugfix: use ?INFO/?ERROR to print log in tcp_listener.erl

Version 0.1.1

Release Date: 2012-09-24

Feature: use rebar to generate release

Feature: support retained messages

Bugfix: send will msg when network error

Version 0.1.0

Release Date: 2012-09-21

The first public release.