The lastmod element is a feature within sitemap files that indicates the last time a URL was modified. It's used by search engines to determine how frequently to crawl pages. As of WordPress version 6.5, this element is natively populated, helping search engines like Google and Bing to understand which content is new or updated, thus improving crawl efficiency and reducing server load.

To check if your WordPress site is using version 6.5, which supports the lastmod element in sitemaps, you can typically find the version number in the admin area of your WordPress site, often at the bottom of the dashboard or in the 'Updates' section. As of now, about 21% of WordPress installs are using version 6.5, so it's a good idea to verify your version to take advantage of improved crawl efficiency.

Updating to WordPress version 6.5 is important for SEO because it integrates the lastmod signal within sitemaps. This signal provides search engines with data insights about when content changes, allowing them to optimize crawling activities and ensure content freshness. This can lead to better online visibility as the latest content is more likely to be found and indexed by search engines.

For non-WordPress websites, implementing the lastmod element in sitemaps requires asking your developers to ensure that the sitemap files include accurate last modification dates. These dates should reflect the last significant changes to the content, with 'significant' meaning changes that might matter to users and search engines.

Combining IndexNow with sitemaps that use the lastmod element offers several benefits for SEO:

• Real-time indexing: IndexNow allows for immediate updates to search engines when content changes.
• Daily catchup mode: Sitemaps with lastmod help search engines keep up with less frequent, but still significant, content changes.

This setup ensures comprehensive coverage and content freshness, which can lead to better online visibility and improved SEO performance.