In November of 2016, Google made the announcement of their mobile-first index that they were planning to launch. After the announcement, Google hoped that it would get enough data to launch completely in the near future. Sadly, Google feels it won’t be ready to launch until the end of the year or in 2018. This update shows that this new index is trickier than first expected by Google’s team.
Knowing this new information also gives webmasters some time to switch to a mobile friendly version or responsive website. In addition, they now have additional time to make sure their websites are optimized for this new index in order to appear in search results once this new index is officially launched.