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GpgOL: MAPI to MIME conversion not working properly with Kopano Server
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For some users the MAPI to MIME conversion in GpgOL is not working. After sending the mail in set looks like it has the PGP Message as the body and it's decrypted like its the body.
As a result the MIME structure is printed into the body and not properly parsed resulted in a broken display, especially if attachments are used. (Our parser does not expect headers for PGP Messages).

The user that showed me the problem uses Kopano 8.3.4-12 through Exchange Active sync.

As I doubt that we can influence the sending we might be able to do some heuristic when reading such a mail e.g. we switch into MIME mode if we see a mime structure in the decrypted / verified content.

A test mail is:

The PGP Message in there decrypts to a valid mime structure.



Event Timeline

aheinecke renamed this task from GpgOL: MAPI to MIME conversion not working properly under some circumstances to GpgOL: MAPI to MIME conversion not working properly with Kopano Server.Mar 6 2018, 10:45 AM
aheinecke updated the task description. (Show Details)

I've started adding a workaround, but shelved it for now. Any workaround would not work for plain signed mails and would not be interoperable with other clients.

I've asked in the Kopano Forum about this, I'm 95% sure the problem is specific to the server / connection. Maybe we can fix that as it's Free Software.


how is the actual state of this point? Is it solved?

I’m wondering if this problem maybe could be a problem of gpb4win and not kopano: there is a alternative gpg plugin existing for outlook 2016 (and other versions) called gpg4o that works perfectly with outlook and kopano.

If you need further data, please let me know…

Kind regards


Hi, gpg4o does not send PGP/MIME (the proper format for including attachments and no encoding problems). As such it does not have the Problem described here. You can use "Send PGP Mails without attachments as PGP/Inline" in the options of GpgOL to have something similar. This will also work for Kopano.

As far as I know the issue is not fixed. It is definitely on the Kopano side, although GpgOL could probably do something to help kopano detect PGP/MIME Mails.

The user who reported this problem to me was not a Kopano customer and I think that Kopano users (ideally customers) would need to ask their devs to look into it.

I'm adding the stalled tag as the ball is IMO not in our court.