SendSafely for Outlook - Legacy Plug-in vs. New Outlook for Web add-in

Outlook Plug-in (Legacy)

The Legacy SendSafely for Outlook plug-in is a VSTO app, which is an older method of integrating with Microsoft Outlook and requires users to install the plug-in locally on their desktop. This legacy plug-in is not compatible with Outlook on the Web and can only be installed on Windows desktops.

We will continue to support the legacy plug-in for the near future, but recommend that users begin to transition to the new add-in when possible. We will eventually be ending support for the legacy plug-in once the majority of our users transition to the newer add-in.

Outlook add-in

In contrast, the new SendSafely for Outlook add-in is built using a newer add-in framework for Outlook that works for Microsoft work and school account across all newer versions of Outlook on Windows and Mac as well as the Outlook Web App (Microsoft 365 and Outlook.com).

The SendSafely Outlook add-in must be installed by a Microsoft Administrator from the Microsoft 365 admin center. Installation instructions are available here. 

The SendSafely Add-in for Outlook is only available and supported for use by Microsoft work and school accounts whose administrator has installed the add-in via the Microsoft 365 Admin Center. The SendSafely Add-in is NOT supported for use by Microsoft personal accounts or work and school accounts where the user installed the add-in directly through the Office Store (not using the Microsoft 365 admin center). If you are unsure which type of account you have, consult this link: What's the difference between a Microsoft account and a work or school account?