What is new for Mail Archiver X version 6.1?

Main new features

Version 6.1 supports the new M1 processors natively. For technical reasons there will be 2 versions of Mail Archiver for a while: an Intel and an M1 version.
Added the new "outline" style toolbar icons of Big Sur as option. You even can have the icons in older versions of macOS:

There are also options to reduce the colors in the interface and to use the compact toolbar style. The latter option is only available for Big Sur and requires a restart.
The loading time for very many emails into the list of emails has been greatly improved.
It is now possible to import old Mail folders directly.

Mailboxes below Inbox and Sent Messages can now be deleted in an archive.
When emails are archived or excluded by flag for mail, there is now an entry in the app log.
It is now possible to reset the fonts in the preferences.
The installer now uses the version string instead of the version number to get version information.
If the path to an archive is not available, there is now an icon indicating that the path is not available. For the internal database, there is an additional message.
The search is no longer executed 2 times.
The disk space warning now takes into account the purgeable and hidden disk space.