NOTE:

• 4.4.0 is in sync with: 4.3.12.
• The build of Windows package has some issues in the current version, we will fix it in the next version.

The compare base of this change set is v4.3.12

Important changes

• For Debian/Ubuntu users, Debian/Ubuntu package (deb) installed EMQ X is now started from systemd. This is to use systemd's supervision functionality to ensure that EMQ X service restarts after a crash. The package installation service upgrade from init.d to systemd has been verified, it is still recommended that you verify and confirm again before deploying to the production environment, at least to ensure that systemd is available in your system

• Package name scheme changed comparing to 4.3. 4.3 format: emqx-centos8-4.3.8-amd64.zip 4.4 format: emqx-4.4.0-rc.1-otp24.1.5-3-el8-amd64.zip

  • Erlang/OTP version is included in the package name, providing the possibility to release EMQX on multiple Erlang/OTP versions
  • centos is renamed to el. This is mainly due to centos8 being dead (replaced with rockylinux8)

• MongoDB authentication supports DNS SRV and TXT Records resolution, which can seamlessly connect with MongoDB Altas

• Support dynamic modification of MQTT Keep Alive to adapt to different energy consumption strategies.

• Support 4.3 to 4.4 rolling upgrade of clustered nodes. See upgrade document for more dtails.

• TLS for cluster backplane (RPC) connections. See clustering document for more details.

Minor changes

• Bumped default boot wait time from 15 seconds to 150 seconds because in some simulated environments it may take up to 70 seconds to boot in build CI

• Dashboard supports relative paths and custom access paths

• Supports configuring whether to forward retained messages with empty payload to suit users who are still using MQTT v3.1. The relevant configurable item is retainer.stop_publish_clear_msg

• Multi-language hook extension (ExHook) supports dynamic cancellation of subsequent forwarding of client messages

• Rule engine SQL supports the use of single quotes in FROM clauses, for example: SELECT * FROM 't/#'

• Change the default value of the max_topic_levels configurable item to 128. Previously, it had no limit (configured to 0), which may be a potential DoS threat

• Improve the error log content when the Proxy Protocol message is received without proxy_protocol configured.

• Add additional message attributes to the message reported by the gateway. Messages from gateways such as CoAP, LwM2M, Stomp, ExProto, etc., when converted to EMQ X messages, add fields such as protocol name, protocol version, user name, client IP, etc., which can be used for multi-language hook extension (ExHook)

• HTTP client performance improvement

• Add openssl-1.1 to RPM dependency