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How to fix: Sitemap <lastmod> within 90 days
Why this matters
AI crawlers use sitemap <lastmod> values to prioritise which pages to re-fetch. A stale sitemap means new or updated content may be missed entirely — and the LLM continues citing your old version for months.
Background
AI crawlers use sitemap <lastmod> values to prioritise which pages to re-fetch. A stale sitemap means new or updated content may be missed entirely — and the LLM continues citing your old version for months.
References
Sitemap protocol spec · AI crawler prioritisation
How to fix
Code snippet for each stack we cover. Pick the one matching your server / framework.
nginx
No server config — application or CMS responsibility.
apache
Same.
cloudflare
Same.
wordpress
Yoast / RankMath generate sitemap with lastmod automatically. Confirm in plugin settings that lastmod is enabled and updates on save.
flask
Generate sitemap programmatically from your content models; emit <lastmod>{{ updated_at.isoformat() }}</lastmod> per URL.
express
Same — generate from a database query.
rails
Use the sitemap_generator gem; emit lastmod from record.updated_at.
Verify it's working
curl https://your-site/sitemap.xml | grep -i lastmod — at least half of the URLs should have lastmod within the last 90 days.
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