Blog Post

Microsoft Defender for Office 365 Blog
5 MIN READ

Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders

Puneeth's avatar
Puneeth
Icon for Microsoft rankMicrosoft
Apr 02, 2025

This applies to Outlook.com - our consumer service, which is supporting hotmail.com live.com and outlook.com consumer domain addresses.

April 29th Update - Changes have been made to the action take on messages that do not meet requirements, please see details below. Introduction In an era where email remains one of the most widel...
Updated Apr 30, 2025
Version 4.0
awareness & training
email protection basics
ats23's avatar
ats23
Copper Contributor
Apr 07, 2025

I would love to hear more about this recommendation: 

  • Compliant P2 (Primary) Sender Addresses: Ensure the “From” or “Reply‐To” address is valid, reflects the true sending domain, and can receive replies.

Will senders have a more challenging path to the inbox if they use mailto:email address removed for privacy reasons as their From: address? When you say "can receive replies," how will this be measured (will you send an email to test, or look for a valid MX record, or ...?)?

ats23's avatar
ats23
Copper Contributor
Apr 08, 2025

Hah! It removed my sample email address for privacy reasons. Replying here so it's clear that my example was noreply @ (sender domain).