[SFDXA] Fix for Thunderbird Email client error that generates question marks in sent emails

[Kai]

I have noticed that some of you who post here are suffering from a Thunderbird 
email client error that generates question marks for multiple spaces or for 
other character combinations. I too had that problem after a Thunderbird 
"upgrade". I tried setting the encode and decode to UTF-8, even on a per-folder 
basis, but that had no effect on the problem.
In my case, I was able to FIX that irritating glitch as follows:

Open Thunderbird email client,
Go to the Configuration Editor (Tools, Options, Advanced, General, Config Editor).
Scroll down to 'mail.strictly_mime'
Click on it and change it from "false" to "true".
Restart Thunderbird.

Be VERY careful when using the Configuration Editor!

If you get another "upgrade" be sure to apply the "fix" again if needed.

With kindest regards,
Kai Siwiak, KE4PT
Secretary for The SFDXA