Verified Confidence: high
Primary source found; it says the same thing, the scope matches, and it is reasonably current.
Safe rephrasing
Microsoft requires domains sending over 5,000 emails a day to Outlook consumer addresses to pass SPF, DKIM and DMARC; non-compliant mail goes to Junk first and may later be rejected.
What the source says
For domains sending over 5,000 emails per day, Outlook will soon require compliance with SPF, DKIM, DMARC. Non‐compliant messages will first be routed to Junk.
Microsoft (Microsoft Defender for Office 365 blog) — Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders
- Commonly cited as
- "Microsoft's bulk-sender rules"
- True origin
- Microsoft (Microsoft Defender for Office 365 blog) — Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders
- Type
- Reference fact: A frequently needed number or rule taken directly from a primary source (e.g. Pew, Census, IAB/PwC, FTC), with its as-of date.
- Year
- 2025
- Data as of
- Announced April 2025
- Last checked
- Method & sample
- Microsoft announcement on its Tech Community blog.
- Drift between quote and source
- Applies to Outlook consumer mailboxes (outlook.com, hotmail.com, live.com)
- Interest
- Microsoft operates Outlook.