A while ago I added a filter that would add a Date: header when one was missing from a message. I have since modified the filters to include adding another date header when the date format was invalid. In both cases I've used a future date (added header is Date: 31 Dec 2025 00:01 -0500). I just tested the same rule in Pegasus Mail modified to utilize the ~y substitution for todays date and it works (Date: ~y).
This is easy to test in Pegasus Mail by manipulating the date header of a .cnm file. How can I test it in Mercury?
Does anyone know if it will even work?