KB-1451 Unsupported API version error when trying to use the Microsoft Outlook Task Viewer Add-in


When configuring the Outlook Task Viewer Add-in in Outlook, the following error occurs:

The API version (1.2) required by this app isn't supported by the Server version that you're connecting to.


The Outlook Server where the Task Viewer Add-in is being installed, is not on a version of Outlook that is supported by the Task Viewer Add-in for Microsoft Outlook.

 The Task Viewer Add-in for Microsoft Outlook is only supported for:

  • Outlook Online (all Appian supported browsers excluding Edge)
  • Office 2016 for Windows
  • Office 2016 for Mac


Upgrade to one of the supported versions of Outlook and use the instructions provided in the Task Viewer Add-in for Microsoft Outlook documentation to configure the add-in.

Affected Versions

This article applies to Appian version 17.3 and later.

Last Reviewed: January 2018