v18.6.0
* :issue:`1776` via :pr:`1851`: Add support for UTF-8 encoded attachment
file names in ``Content-Disposition`` header via :rfc:`6266#appendix-D`.
v18.1.2
* Fixed :issue:`1377` via :pr:`1785`: Restore a native WSGI-less
HTTP server support.
* :pr:`1769`: Reduce log level for non-error events in win32.py
