WPCred was kind enough to include Postie in their survey of email plugins.

• Fixed an issues with plain text posts and the new class name wrapper.

• Deal with possibility of no post format specified (reported by @rogerlos)
• Add surrounding div with postie-post class name for CSS rules for themes.

• if any attachment doesn’t have a file extension use the secondary mime type

• remove Allow HTML In Mail Body from settings as it didn’t do anything
• add Allow Duplicate Comments setting to deal with WordPress killing the import
• fix issue where unknown email was leaving tmppost, now creates draft message
• add setting to disable legacy commands

• Add post id to action postie_comment_after
• remove Create Alternate Image Sizes from settings as it didn’t do anything
• Add compatibility for WordPress 5.7

• Add postie_subject filter

This filter is called after the subject has been determined. Note that the subject can be in the email subject or the email body. You could use this filter to modify the subject before categories, post format and post type are detected.

add_filter('postie_subject', 'my_postie_subject');

function my_postie_subject($subject) {
    return '[promo] ' . $subject; // force the addition of the promo category
}

• Fix issue with detecting categories when there are multiple colons in the subject line

A series of releases to help track down an environmental issue for a customer.