[MM3-users] MM attaches mime-attachments to mail as text file since update to 3.3.8

Dear Users & Developers,

we're running MM3 on Ubuntu 22 and used the venv-installation method. Last week we updated via¹ to

Mailman Core-Version GNU Mailman 3.3.8 (Tom Sawyer) Mailman Core API-Version 3.1 Mailman Core Python-Version 3.10.6 (main, Nov 14 2022, 16:10:14) [GCC 11.3.0]

and now mailman attaches mime-attachments to email as text-files. That breaks many mails in our environment.

For example: Now we have attachments like

smime.p7s + ATT000001.txt as well as what looks like MM footers "mailing list --- test@domain ... To unsubscripbe send an email to ..."

How can we get the "old" processing back?

Thank you alot.

Stefan