For latest updates on HVE, please also see this post.
High Volume Email (HVE) for Microsoft 365 allows customers to send large volumes of email, primarily to internal recipients without any recipie...
Updated May 06, 2025
Version 3.0
Blog Post
Our use case for HVE isn't High Volume Email, but rather multifunction device scan-to-email via basic authentication. Currently, this is achieved using a licensed Exchange Plan 2 account with all services disabled except for SMTP Auth.
The 10 MB attachment size limit for HVE is a significant obstacle for our use case, hindering a seamless migration.
jim0thy raises some excellent points. It feels like this rollout is rushed, with the deprecation of SMTPAUTH and HVE entering public preview in the same month. We still don't have pricing information and now we'll be paying for a service that was previously included in a P1/2 license. Additionally, there's a lack of feature parity for customer use cases like attachment size and reply-to functionality.
Simone_LiebalMicrosoft
itbbqtommy Thank you for your feedback! Could you share more information about your use case for attachments and specifically what attachment sizes you typically encounter in your environment?
jim0thy Thank you also for you feedback! Regarding pricing: We are currently in process of finalizing pricing and will share more information soon. We are aware that this is an important factor in choosing the right solution for you, so we will share this information before HVE goes GA.
Additionally, HVE allow significantly sending higher volumes, than is currently possible with the Exchange Online user mailbox limits.