<b>SOP: Make lastmod tell the truth</b>

<b>SOP: Make lastmod tell the truth</b>

Google ignores sitemaps whose lastmod lies. Run this before every push:

— ✅ lastmod changes ONLY when the indexable content changed (body, title, canonical, structured data)
— ✅ A footer/year/comment-count edit does NOT bump lastmod
— ✅ Value is full W3C datetime with timezone: <code>2026-06-13T08:00:00+00:00</code>, not just a date
— ✅ Max 5% of URLs carry today's date on any given crawl

Fail criterion: if your CMS sets lastmod = NOW() on every regen, Google learns to distrust the field and stops using it for scheduling. That is the single most common reason lastmod gets silently dropped.

Fix: store a real <code>content_hash</code> per URL. Update lastmod only when the hash changes.

Definition of done: spot-check 10 unchanged URLs across two crawls — all 10 keep their old lastmod.