Submit an XML sitemap with lastmod values that change only on significant updates
| Impact | Evidence | Applies to | Last checked |
|---|---|---|---|
| Medium | Official guidance | Google, Bing | Oct 30, 2026 |
Why it matters
Google uses lastmod only when it is consistently and verifiably accurate, and a copyright year change does not count. Sitemaps are capped at 50,000 URLs or 50 MB uncompressed. They are also a weak canonical signal, so list only canonical URLs.
How to do it
- Generate the sitemap from your CMS or build so lastmod reflects real content edits
- Reference it with a Sitemap: line in robots.txt and submit it in Search Console and Bing Webmaster Tools
- Split into a sitemap index above 50,000 URLs
- Exclude redirected, noindexed and non-canonical URLs
Sources
- Build and submit a sitemap · Google Search Central, Jul 8, 2026
Change history
| Date | Change | What changed |
|---|---|---|
| Oct 30, 2026 | Added | Added to the rulebook. |
Checked against its sources every Monday. Only content changes are listed.