This is a bugfix release. The important changes are fixing the on_log() callback in the Python module and the log_dest option when running as a Windows service. The rest of the fixes are documentation and build script fixes.

Downloads are available on the download page and include all supported binaries (except for Ubuntu packages which are still waiting to build due to Launchpad maintenance). The Python module has been uploaded to Python Package Index.


  • Fix default log_dest when running as a Windows service.

Client library

* Fix incorrect parameters in Python on_log() callback call. Fixes bug #1036818.


  • Clients now don't display TLS/TLS-PSK usage help if they don't support it.

Build scripts

  • Fix TLS-PSK support in the CMake build files.
  • Fix man page installation in the CMake build files.
  • Fix SYSCONFDIR in cmake on *nix when installing to /usr. Fixes bug #1036908.


* Fix mqtt/MQTT capitalisation in man pages. * Update compiling.txt. * Fix incorrect callback docs in Fixes bug #1036607. * Fix various doc typos and remove obsolete script. Fixes bug #1037088.