After 16.09 which brought a lot of improvements, the last version for 2016 includes a big refactor we have been preparing for long time, and a couple of new features that pursue the central effort on API, commands and web integration started early this year.
ejabberd 16.12 includes: a new API permissions framework for commands, a new more reliable BOSH module, major code refactor, more integration and unit tests, improved support for Erlang/OTP R19, compatibility with rebar3 build system and many fixes and optimizations.
Read more at https://blog.process-one.net/ejabberd-16-12-beta1/