New indexing will become a default by September
Google announced it will switch to mobile-first indexing for all websites starting September 2020.
Mobile-first indexing is crawling the web using a smartphone Googlebot instead of the desktop bot. Google search primarily uses a mobile version of the webpage for generating search indexes and ranking.
Google pushed for the adoption of the mobile-first indexing for a few years now.
The company had first outlined its efforts around mobile-indexing in 2016.
Recognizing these changes may take some time for specific domains, Google switched them to mobile-first indexing only when it recognized the websites were ready. After that, Google still occasionally crawled sites with the conventional desktop Googlebot, but executed the majority of the search crawling with the mobile smartphone user-agent.
According to Google, 70% of websites that appear on the search engine result pages (SERPs) have already shifted over. For this reason, Google began a more forceful transition and decided to make mobile-first indexing a default later this year.
“Mobile-first indexing has come a long way. It’s great to see how the web has evolved from desktop to mobile, and how webmasters have helped to allow crawling & indexing to match how users interact with the web!” stated Google in its official blog.
Previously, Google published the guidelines for the mobile-first indexing. The webmasters who want to check if their site is ready for the transition can use the URL Inspection Tool.