Google Says All Sites To Be Switched To Mobile First Indexing Within 6-12 Months

Google is sending out notifications for mobile-first indexing issues detected on your site. And in that notification it says “Google expects to apply mobile-first indexing to all websites in the next six to twelve months.” Yes, probably by the end of this year, all indexing will be done using mobile-first indexing at Google.

So I would take these notifications seriously if you get one. You have less than a year to make sure your site is ready for mobile-first indexing, if it has not yet been switched over.