Outlook Sales Extension

HubSpot Product Team
HubSpot Product Team

Ending Development for HubSpot's VSTO Sales Add-In


Microsoft recently announced a new version of Outlook that does not support VSTO add-ins, and with that its intention to move away from the VSTO add-in framework entirely. This announcement naturally impacts the HubSpot Sales VSTO add-in along with any other VSTO add-in. This article will explain the impacts and the potential solutions. 


About the Microsoft release

Microsoft has announced a fundamental change to Outlook for Windows and as a part of the release, VSTO add-ins will no longer be supported in the new Outlook for Windows.

The full announcement is posted on Microsoft's Support page:

Additional information is available on the Microsoft Community:


How the Microsoft release will impact HubSpot customers

HubSpot has two different add-ins that can be utilized in Outlook-based email clients:

Both add-ins are functionally the same and allow HubSpot customers to track and log emails and use HubSpot’s sales tools directly inside their Outlook-based email clients. 


The VSTO add-in is only compatible with Outlook for Desktop on a Windows machine. 

The web add-in is compatible with Outlook for Desktop on PC and Mac, as well as web-based Outlook applications. 


Over the past few years, HubSpot customers could choose between these two HubSpot add-in options when working with Microsoft email clients.  Going forward HubSpot customers should use the web add-in to integrate HubSpot’s sales functionality into their email. As Microsoft extend support to additional inbox providers (e.g. IMAP, POP3, Yahoo, etc. ), customers can move to the new Outlook for Windows and leverage the web add-in.  


HubSpot customers on the new version of Outlook will have full support with the HubSpot Sales web add-in (available for download here). 


As part of this announcement, HubSpot is also planning to deprecate its HubSpot for Windows notification application (deprecation date: January 25, 2024). Email notifications can now be delivered by HubSpot’s browser-based notification system (read more here). 


What this means for HubSpot customers


With Microsoft’s new release, HubSpot will no longer actively develop or improve the HubSpot Sales VSTO add-in. However, the VSTO add-in should continue to work in legacy versions of Outlook as long as Microsoft supports those versions, and HubSpot will continue to support the HubSpot Sales VSTO add-in within these legacy versions of Outlook for now.


HubSpot customers on legacy versions of Outlook will be able to continue using the VSTO add-in as long as those Outlook versions remain supported by Microsoft. Because HubSpot will no longer actively develop or improve the HubSpot Sales VSTO add-in, it is highly recommended that HubSpot customers activate the HubSpot Sales Office 365 add-in.


How to transition to the new Outlook for Windows



HubSpot customers will have various opportunities to transition to the new version of Outlook over the coming months. 

HubSpot recommends distributing the web add-in for Outlook starting now because:

  • Only web add-ins will be supported in the new Outlook
  • By deploying the web add-in to Outlook users today, additional workload once Microsoft pushes the new Outlook can be avoided
  • The web add-in is available across PC, Mac, and Office online. 


How to disable transitioning to New Outlook

End-users can manually disable the New Outlook by toggling off the "New Outlook" toggle in the ribbon. Note that this option is only needed for HubSpot customers on temporarily incompatible inbox providers (e.g. IMAP, POP3, Yahoo, etc.) while Microsoft works to support these inboxes in the new Outlook for Windows email client. 

Customers IT can support end-users by deploying a registry key to the users to hide the "Try the new Outlook" toggle or to disabled mailbox access in the new Outlook: 



Will users that are not hosted on O365 will be able to use the O365 add-in?

Does the O365 add-in require a connected inbox?

  • Yes, the requirement to connect the inbox is still unchanged. 

Do you have any questions or comments?


Join the discussion here 

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