• Fix for OSX compilation issue on vmq_passwd due to openssl headers not found.
• Refactoring to further abstract and generalize the Plumtree metadata layer.
• Small refactoring moving the calling of plugin hooks into the fsm code. This
  is a preparation for MQTTv5. Note, this change has an impact on the
  vmq_reg:direct_plugin_exports/1 function. Even though this function is
  internal and as such not guaranteed to be stable, we know some plugin
  developers use it and we therefore wanted to describe the changes. It works as
  before, except that the hooks auth_on_subscribe, on_subscribe or
  on_unsuscribe hooks will no longer be called when using the exported
  functions.
• Corrected a few spelling errors in the vmq-admin help commands.
• Added two new hidden configuration parameters for vmq_webhooks. vmq_webhooks uses
  the hackney HTTP client for HTTP requests.
  It starts its own hackney pool with a default connection pool of 100, and a
  connection timeout of 60000 milliseconds. This connection pool con now be
  configurable using the settings vmq_webhooks.pool_max_connections and
  vmq_webhooks.pool_timeout (#621).
• Add a first version of a VerneMQ status page showing node and cluster
  information. This web-page is by default available on
  http://localhost:8888/status. The status page is implemented using jQuery,
  Twitter Bootstrap und mustache.js. As this is the first version the page
  should be considered experimental and will likely be changed in future
  releases.
• Bugfix: Handle return values correctly when enqueuing messages to offline
  shared subscribers (#625).
• Bugfix: Fix issue preventing messages delivered to a subscriber group from
  being delivered to the online group members first before attempting delivery
  to offline queues (#618).
• Fix some Dialyzer issues.
• Reduce replication load during a netsplit by making sure data is not attempted
  to be replicated to unreachable nodes.
• Bugfix: Fix issue causing some session show options (peer_host,
  peer_port) to not work for websocket clients (#542).
• Bugfix: Fix routing table initialization issue after restarting a node
  preventing shared subscriptions on a remote node from being included in the
  routing table (#595).
• Bugfix: Fix race condition when fetching data from the internal query subsystem.
• Fix build issue on Raspberry PI (make rpi-32).
• Make it possible to specify which protocol versions are allowed on an MQTT
  listener. By default the protocol versions allowed are versions 3 and 4 (MQTT
  v3.1 and v3.1.1 respectively). To set the allowed protocol versions one can
  use listener.tcp.allowed_protocol_versions = [3,4] on the transport level or
  for a specific listener using
  listener.tcp.specific_listener.allowed_protocol_versions.
• Fix bug causing an exception to be thrown when vmq-admin cluster leave is
  used with a timout value less than 5 seconds (#642).
• Small refactoring enabling to store versioned message store values. This is a
  preparation for MQTTv5.
• Bugfix: Fix a bug that prevented user plugins with an explicit path to be
  loaded.
• Fix issue with new rebar3 upstream plugin version (the port-compiler) which
  made builds fail by pegging it to an older version (1.8.0).
• Add xmerl and inets from the Erlang standard library to the release in order
  to allow plugin developers to have these libraries available.
• Bugfix: Fix typo (graphie_api_key -> graphite_api_key) preventing the
  graphite api key from being set in the vernemq.conf file.
• Bugfix: WebHooks Plugin. Close the Hackney CRef so that the socket is given
  back to the Hackney pool, for the case of non-200 HTTP OK status codes.
• Bugfix: fix bug where queries with mountpoint and client-ids would return no
  entries causing disconnecting a client with a specific mountpoint to
  fail. Also ensure to use the default mountpoint if no mountpoint was
  passed. (#714).
• Upgraded vernemq_dev to include the disconnect_by_subscriber_id/2 API.