Version: (using KDE Devel) Installed from: Compiled sources Outlook and exchange do not use the rfc optional headers, but instead use the proprietary headers "Thread-Topic:" and "Thread-Index:". Just about every mailer on earth uses the optional rfc headers as outlined at http://www.dsv.su.se/jpalme/ietf/message-threading.html including kmail. Kmail has recently gone one step further and added support for threading by subject which helps with such broken messages. It truely would great if kmail where to add support for threading using these Microsoft headers, as they are increasingly common in mails. The "Thread-Topic:" header is straight forward, but some kind of reverse engineering is probably needed with the "Thread-Index:" header as its probably undocumented. I can provide examples of messages containing these headers if required.
You say "they are increasingly common in mails" -- is this because other e-mail clients are falling for the "embrace, extend, exterminate" trap, or is the relative percentage of microsoft-based clients increasing? I can't help but think that "supporting" this non-rfc header is playing right into microsoft's hand -- they may be prepared to "drop" this overnight thus making everyone else's "client" look like it's broken [consider the possibility that they have some other header already defined -- outlook and exchange may already have the code in place to use the "new, as yet undocumented header" and simply have it "triggered" by receiving a message with that header. Result: at the drop of a hat, Microsoft can force everyone that "complies" with their way of thinking into a re-write...] If it is the second case, (that the relative number of outlook/exchange clients & servers is increasing,) well, dunno what to say to that...
I think its very much the second case. Outlook/exchange is the only client that I know uses these headers. I don't think anyone has of yet reverse engineered the "Thread-Index" header and thus been able to use them. Certainly no linux client I can find uses them (i've raised wishlist bug reports with several to add support, as I'm doing with kmail). I've after asking around, to other windows client seem to use them either. (But then "most" windows users use outlook/exchange) It is rather annoying that outlook/exchange does not use the rfc optional headers for threading as just about every other client in exsistance does, but given its pervasivness, supporting these prioprity headers seem like the only option. (given the unlikelyness of microsoft falling into line and using the rfc optional headers.)
Thank you for your feature request. Kmail1 is currently unmaintained so we are closing all wishes. Please feel free to reopen a feature request for Kmail2 if it has not already been implemented. Thank you for your understanding.
Instead of creating a new feature request, please confirm here if the wishlist is still valid for kmail2.
Still applies to kmail2, component: message list.
Thanks for the update.