• Ensure mountpoints specified at the protocol level are inherited on the
  specific listeners.
• Fix missing output from vernemq version (#1190).
• Ensure errors from the parser variable decode are handled correctly and logged
  at the debug level instead of causing a crash in the socket process.
• Handle list of sec-websocket-protocol correctly (#1149) in the websocket
  implementation.
• Ensure that plumtree application isn't started when metadata plugin SWC is used.
• Fix bug preventing restarting Lua states properly in case of a crashing script.
• Fix warnings due to deprecated lager configuration (#1209).
• Upgrade lager to version 3.7.0 (In preparation for OTP 22 support).
• Make VerneMQ run on Erlang/OTP 22.
• Add new webhooks CLI register flag --no_payload=true which, if enabled, will
  remove the MQTT payload from the JSON object send via the auth_on_publish
  and auth_on_publish_m5 payloads. The flag can also be set in the config file
  using vmq_webhooks.hookname.no_payload=on.
• Add metric client_keepalive_expired which tracks clients that failed to
  communicate within the keepalive time.
• Expose the crypto:hash/1 function in LUA, for example to do a 256bit sha3
  hash one can call crypto.hash("sha3_256", data). The hashing algorithms
  supported are exactly the ones supported by the crypto:hash/1 function and
  may change depending on the Erlang/OTP version used to build Erlang. See the
  complete list of supported hashes here:
  http://erlang.org/doc/man/crypto.html#Digests%20and%20hash. If passed an
  unknown hashing algorithm an error is raised.
• Fix prefix handling in the bridge plugin (vmq_bridge).
• Strengthen parameter validation in the bcrypt.hashpw/2 LUA function in
  vmq_diversity.
• Pass arguments correctly to vmq-admin when called via sudo.
• Handle rate metric labels correctly in the example grafana dashboard.
• Upgrade cowboy to version 2.6.3 as well as cowlib and ranch to versions 2.7.3
  and 1.7.1 respectively. This update also means the PROXY protocol code was
  removed and the PROXY support from cowboy is used instead.
• Handle retained flag in the bridge plugin (vmq_bridge).
• Ensure systemd doesn't terminate VerneMQ if it is slow to start.
• Implement bridge protocol handling (protocol version 131) for bridges
  connecting to VerneMQ such that the retained bit is kept on messages routed to
  the bridge (Retained as Publish) and messages coming from the bridge are not
  forwarded to the bridge if it has a matching description (No Local).
• Fix message store startup consistency checking routine which resulted in
  potentially deleting wrong messages in cases where an inconsistency was detected.
  This fix also increases message storage performance during startup as well as
  during normal operation. However, the nature of the bug and the provided solution
  don't enable a simple downgrade path and introduces a backward incompatibility if
  a VerneMQ message store containing offline messages has to be downgraded to 1.8.0
  or earlier versions.
• Upgrade dependency cuttlefish to version 2.2.0.
• Improve large queue initialization performance by reducing algorithmic
  complexity from O(n^2) to O(nlogn) where n is the number of offline messages.
• Add the ability to modify the username on auth_on_register and auth_on_register_m5
  hooks. Supports both vmq_diversity and vmq_webhooks.
• Upgrade the vmq_diversity redis driver eredis to version 1.2.0.
• Fix vmq_diversity supervisor restart shutdown issue (#1241).