The GA date for this feature has been moved to March 2026. For latest updates on HVE, please also see this post.
High Volume Email (HVE) for Microsoft 365 allows customers to send large volumes of ...
Updated Oct 06, 2025
Version 5.0
Blog Post
Is it possible to add the HVE account to Outlook? Chipper2225
Not sure what you mean by add to Outlook. once you create the HVE account is acts as a mailuser without a mailbox from what I can see. If you have an existing account you want to send as, you can add it to the delegation of that mailbox to send. haven't tested sending yet but it does let you add the HVE account to another account as delegated access.
Simone_LiebalMicrosoft
Chipper2225 Send-As is not yet supported, but we are planning on adding this functionality as one of the first improvements post-GA.
Thank you Simone_Liebal . I did test this and yeah this definitely does not work to use send-as an existing mailbox.
Do have another question when you have a minute.
If we use HVE since that will allow basic auth still, do we need to exception out the service accounts from any CA policies that block legacy auth? We are getting ready to turn off legacy off once we address all the SMTP users but as a precaution, would like to exclude them out if they are impacted at all. thanks