TMail handles the “content-type” header field per RFC 2045.
Per the RFC you can not use /[?/=]/ in the boundary=field unless it is
quoted, MS Outlook Express (at least) violates this rule.
The fix is to check the boundary= value for the special characters and
wrap it in quotes if the special characters exist and the field is not
I have written a patch with failing tests for this and sent it to the
Maintainer, for anyone else, you can get it now and apply it to TMail
0.10.8 from here: