Google is deprecating the ten-year-old Sitelinks Search Box. It is going to start to disappear from the search result snippets starting on November 21, 2024. This does not impact the normal sitelinks, just the search box.
Google wrote, "It's been over ten years since we initially announced the sitelinks search box in Google Search, and over time, we've noticed that usage has dropped. With that, and to help simplify the search results, we'll be removing this visual element starting on November 21, 2024."
I sometimes found this feature pretty useful but hey, I guess Google noticed most searchers did not?
"This update will roll out globally across all search results, in all languages and countries," after November 21st.
"This doesn't affect rankings or sitelinks otherwise, and won't be listed in the Search status dashboard," Google added.
Google added, "Once we stop showing sitelinks search box elements in Search, we'll remove the Search Console rich results report for it and stop highlighting the markup in the Rich Results Test. While you can remove sitelinks search box structured data from your site, there's no need to do so. Unsupported structured data like this won't cause issues in Search, and won't trigger errors in Search Console reports. If you decide to remove sitelinks search box structured data, note that site names also uses a variation of WebSite structured data, which continues to be supported."
Forum discussion at X and WebmasterWorld.