Gary Illyes from Google ranted on Bluesky about folks updating the lastmod date in their sitemap files when all they have changed was the date in their footers copyright line from 2024 to 2025. Gary said, don't do it, it is not enough of a change to the page's content to warrant a lastmod date update.
Gary posted on Bluesky in all caps:
O.M.G. PEOPLE! UPDATING THE COPYRIGHT YEAR IN THE BOTTOM OF YOUR PAGES IS NOT A SIGNIFICANT UPDATE, NO NEED TO UPDATE YOUR LASTMOD
Yea, SEOs tend to update the lastmod date too often and maybe some of that blame as to do with the CMS they are using but still.
Just changing the footer text is not enough of a reason to tell Google the page changed, you should only update the lastmod date when the text on the page changed in a larger way.
The question is how much of a change is enough, in which Gary replied to saying:
We purposefully don't define "significant", or so I think anyway. In my view, changing the actual content is significant, but iirc johnmu would also add schema and linking changes. However I'm pretty sure we both agree that changing the copyright date is not significant.
Forum discussion at Bluesky.
