the Python mailbox and mail modules would allow this And other tasks https://covrebo.com/parsing-mbox-files-with-the-mailbox-library.html
Re https://sourceforge.net/projects/hermesmail/files/ It would be nice to update the "About" box and title bar to reflect the versioning. I have both and it would be best to differentiate at a glance if nothing else. Resource Hacker is tricky to make those changes without the code throwing warnings.