sitemap.xml de <lastmod> a sadece yıl-tarih-gün şeklinde yazsak sorun olur mu ? Birde bu şekilde kullanım doğru mu ?

<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
<!--  created with Free Online Sitemap Generator www.xml-sitemaps.com  -->


<url>
<loc>https://siteadi.com/</loc>
<lastmod>2019-09-21T16:12:20+03:00</lastmod>
</url>