Google’s Gary Illyes told developers to strip the lastmod field from XML sitemaps entirely when the dates cannot be trusted. Illyes made the recommendation on Bluesky, responding to a question raised in Search Engine Roundtable’s July 16 coverage: “probably better off without the lastmods. at least you save a few bytes.” The stakes reach beyond storage: an inaccurate freshness signal actively misleads crawlers about which pages changed.
The field is supposed to flag the last time a page’s content meaningfully shifted. Plenty of deploy pipelines instead rewrite the timestamp on every URL with each release, regardless of whether anything on the page actually moved. That mismatch is the specific failure mode Illyes is warning against: once Google catches a site misreporting freshness, it starts discounting the whole sitemap’s dates, even the accurate ones.
The fix is not technical. Teams that cannot verify their build process ties lastmod to real content edits should remove the field rather than keep shipping noise. A clean sitemap without lastmod outperforms one Google has learned to distrust.
Search Engine Roundtable reported Gary Illyes’s comments on July 16, 2026.
