0.4.0

Drop support for Python <3.6
Switch to github actions for CI
Reformat entire project with black and add pre-commit
Add assume_markdown config option

0.3.5

Fix some unicode handling (including, hopefully, fixing non-ASCII subject lines for real)
Drops support for Python 3.3 and Python 3.4 since we depend on libraries that have dropped support for them
Add support for Python 3.7 and Python 3.8

0.3.4

Fix regression in headers from 0.3.0 with some multipart/signed messages
Fix regression in passthrough mode from 0.3.3 on Python 2; add better testing

0.3.3

Fix -s / smtp passthrough mode on Python 3

0.3.2

Fix smtp_password_command
Fix tests with newer version of pytest

0.3.1

Fix an incompatibility with Python 3.5

0.3

Add a man page (contribution by @ssgelm)
Split sendmail command on whitespace (contribution by @nottwo)
Fix a ton of bugs with MIME tree construction
fix tests