Sitemap Lastmod Churn

Checks that sitemap lastmod values aren’t all stamped with the same build date

Rule ID	crawl/sitemap-lastmod-churn
Category	Crawlability
Scope	Site-wide
Severity	warning
Weight	4/10

Solution

If every URL in your sitemap carries the same (or nearly the same) lastmod date, the field is being stamped at build/deploy time rather than reflecting real content changes. This makes lastmod useless as a freshness signal - search engines may learn to ignore it entirely. Update lastmod only when a page’s content actually changes, driven by your CMS or version control history, not by the deploy pipeline. Google News sitemaps are excluded from this check: they hold only about 48 hours of articles by design, so their lastmod values are supposed to cluster.

What this rule does not count

Google News sitemaps are excluded. A news sitemap (one declaring the xmlns:news namespace) carries roughly the last 48 hours of articles by specification, so its lastmod values always fall on one or two days. Counting them would flag every publisher that has one. Detection is by namespace, not filename, so a news sitemap served from any path is recognised.

If the only lastmod values found on your site come from a news sitemap, the check reports as skipped and says so, rather than reporting a problem you do not have.

The check needs at least 20 URLs carrying a lastmod (news-sitemap URLs excluded) before it will judge anything. Below that it skips, because a handful of pages legitimately updated in the same week is indistinguishable from a build stamp.

Enable / Disable

Disable this rule

[rules]
disable = ["crawl/sitemap-lastmod-churn"]

Disable all Crawlability rules

[rules]
disable = ["crawl/*"]

Enable only this rule

[rules]
enable = ["crawl/sitemap-lastmod-churn"]
disable = ["*"]