RTF mail format

Is is possible to implement in k9mail RTF (rich text format) mails in k9mail?

Users receiving mails from outlook with attachments can’t see them. Attachments comes in winmail.dat format.
I remember being able to open simple .doc files in the past with k9mail but no longer possible.

Best regards,

You need to get the senders to fix their email settings. There is no shortage of online resources to assist those who have misconfigured their email in such a fashion.