Zimbra SkillZ: Confidential Header Zimlet

Hello Zimbra Customers, Partners & Friends,

The Confidential Header Zimlet implements the reading and setting of the Sensitivity header RFC2156 in the Zimbra Modern UI. For consistency, it is implemented the same way as in MS Outlook.

Configuring Zimbra

To allow the setting of the Sensitivity header, enable it on the Zimbra server:

zmprov mcf +zimbraCustomMimeHeaderNameAllowed Sensitivity


Sensitivity Header in Zimbra


Sensitivity Header in Zimbra Email


Sensitivity Button in Email Compose Window


Sensitivity Dialog Box


Sensitivity Header in Outlook


Setting Sensitivity Header in Outlook

Further reading


Your Zimbra Team

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2 Responses to Zimbra SkillZ: Confidential Header Zimlet

  1. SB May 23, 2022 at 4:37 AM #

    Hi Barry,

    i was trying to implement this zimlet and the functionality worked fine. But in one scenario i am getting stuck, if i mark the mail as confidential and send it it works fine, but if in the same session i send another mail after the first mail without marking it as confidential then also the confidential header is attached to the second mail.

    Ideally the header should be applied for only that mail where i have marked it as confidential. Please suggest if i am doing something wrong or what can i do to avoid this.

    • Avatar photo
      Barry de Graaff May 23, 2022 at 4:50 AM #

      Hello Rebel,

      Thanks for reporting this bug, it has been fixed and a new version can be downloaded from Github. Don’t forget to `zmprov fc all && zmmailboxdctl restart` and flush your browser cache after installing the new version.


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