Created attachment 148671 [details] the mail with the pdf SUMMARY *** some jointed pdf are by default opened by kate *** STEPS TO REPRODUCE 1. click on pdf 2. 3. OBSERVED RESULT kate opens the pdf EXPECTED RESULT okular opens the pdf SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.24.5 KDE Frameworks Version: 5.93.0 Qt Version: 5.15.2 kde gear 20.04.0 ADDITIONAL INFORMATION If I display the properties of the PDF, I get "Type : text/plain" .
KMail reads the file type from the message data. The relevant part of the mbox file is --_f1fdcbb7f3b911688bff11751fa7d1a8 Content-Type: {"application/octet-stream"}; name="certificat_1-A8T121_20220509122829.pdf" Content-Disposition: attachment; filename="certificat_1-A8T121_20220509122829.pdf" Content-Transfer-Encoding: base64 When I manually change it to Content-Type: application/octet-stream it works as expected