Why are the VSTO Add-ins not following my Outlook language settings?

In order to make sure that the VSTO add-ins follow the Outlook language, please make sure you have the latest version of the add-ins installed.

 To check this, please go to the "Add or Remove Programs" Control Panel section in Windows and click on the installed add-ins. The version number will be displayed like this:

 

Workplace Outlook Add-in version

 

The latest version of the add-ins is: 1.4