Claus-Justus Heine via Mailman-users writes:
Kind thanks for the response. I have to apologize: my "test user" had its preferred language set to en_US, so that was the reason for the question marks. So this was indeed a user-error (i.e. my fault).
But we'd like to have that user get the English version of the message. One of two things seems reasonable:
You have customized the German template, but not the English template. In that case, I think it makes sense for Mailman to assume the German template has important information that the English does not, and send the German template with its appropriate encoding (UTF-8, nowadays). The fact that en_US can be encoded in ASCII should not affect the encoding of the de template, ever.[1]
You have not customized the German template. In that case the user should get the default English template.
How do those sound to you, as goals for Mailman behavoir?
So ISTM this is a Mailman issue, if Mailman is sending out the German message with question marks substituted for non-ASCII characters, or if Mailman is sending out the German message with US-ASCII as the Content-Type charset parameter. The only way I can see this as a user (admin) issue is if you overwrote the English template with German (and even then, it's nuts for Mailman not to use UTF-8 for English what with directed quotes, emoji, and all the other enhancements to the character repertoire that US English speakers use).
Can you tell me a little more about whether you configured any custom templates, and if so, how? That is, did you use the Postorius text field or overwrite files directly?
Steve
Footnotes: [1] Note to self: perhaps the admin UI can check the list of supported languages and warn if some but not all are customized.