Thunderbird in particular is known to be problematic. Thunderbird
users may wish to visit this web page for more information:
- http://kb.mozillazine.org/Plain_text_e-mail_-_Thunderbird#Completely_plain_email
+ https://kb.mozillazine.org/Plain_text_e-mail_-_Thunderbird#Completely_plain_email
SEE ALSO
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