Email sender rules: changes log

This log lists changes to the sender rules of Gmail, Yahoo and Microsoft (Outlook.com). Each entry has a date and a link to the provider's own page. Newest entries are at the top.

• 1 November 2025 · Gmail

  Gmail says it is ramping up enforcement on mail that does not meet its sender rules. Such mail can see temporary and permanent rejections.

• 5 May 2025 · Microsoft (Outlook.com)

  Outlook.com rules for domains sending over 5,000 emails a day take effect: SPF and DKIM must pass, DMARC at least p=none and aligned. Announced 2 April 2025; on 29 April 2025 Microsoft said failing mail would be rejected with error 550 5.7.515.

• 1 June 2024 · Gmail

  Deadline for bulk senders that already had an unsubscribe link to add one-click unsubscribe to marketing mail. From June 2024, bulk senders with a spam rate above 0.3% cannot get delivery help.

• 1 February 2024 · Gmail

  Gmail's sender rules take effect: SPF or DKIM for all senders; SPF, DKIM, DMARC, alignment and one-click unsubscribe for bulk senders; spam rate below 0.3%.

• 1 February 2024 · Yahoo

  Yahoo's sender requirements take effect: SPF, DKIM, DMARC, one-click unsubscribe and a low spam rate for bulk senders. Yahoo rolled out enforcement gradually through the first half of 2024.

This is our summary, not the provider's official text. Rules can change; always check the linked source.