Invalid date when submitting Google XML sitemap

Question

When validating my XML sitemap, google says:

Invalid date An invalid date was found. Please fix the date or formatting before resubmitting.

I convert the mysql timestamp by:

gmdate('Y-m-d\TH:i:s', strtotime($row['modified']['value']))

Answer 1

The 'lastmod' element has to be of the format YYYY-MM-DD or YYYY-MM-DDThh:mmTZD so use:

gmdate('Y-m-d', strtotime($row['modified']['value']))

or

gmdate('Y-m-d\TH:i:s+00:00', strtotime($row['modified']['value']))

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