- update to 3.14:
* New `digest-type` configuration adds optional more widely supported `multipart/mixed` format
* New argument `--only-new` on the `add` command to ignore entries in feed
when added, so only new entries will be sent.
* Fix exception when parsing a feed with a linebreak in its title
* Add a new `subject-format` setting, customise the subject line
* Removed '$' interpolation in config file to allow URLs containing dollar
signs. Interpolation was not fully supported, and the placeholder would not
survive a second save. Config files with ${...} placeholders will need to be
manually edited after upgrading, or a save forced by adding and removing a fake
feed before upgrading.
* Fix default HTTP User-Agent to use `rss2email` instead of `feedparser`, and
fix `user-agent` setting to consistently apply to both outgoing emails and
HTTP requests. This introduces a couple of potentially breaking changes:
o Configurations that came to rely on the `feedparser` UA string should adjust to the updated UA string going forward.
o Configurations that came to rely on the unintended behaviour, that
configuring the User-Agent header in emails does not affect HTTP requests,
should use a custom `post-process` hook instead.