Atom date test http://example.com/ 2026-05-19T22:43:20+00:00 Has both dates http://example.com/both 2026-03-17T17:35:43+00:00 2026-05-19T22:43:20+00:00 Only updated http://example.com/updated-only 2026-05-04T16:56:28+00:00