Google on webmaster blog declared that they will be boosting the effects of mobile- friendly algorithm that they launched back on April 21, 2015.
According to Google update will take place in the beginning of May and it also increases the effect of mobile friendly ranking signals. According to Google this update will affect those who are already mobile- friendly.
When this update will take place, major drop-off on non mobile friendly websites won’t be seen when the algorithm is pushed out. This kind of sounds like the slow Panda 4.2 rollout but it is still not clear whether the roll out will take weeks or months. According to Google it will take place in the beginning of may.
As mobile-friendly update is a page-by-page signal, it can take time for Google asses each and every page. And depending on how fast Google crawls and indexes all of the pages on your site, the impact can be slow to show up.
This roll out will have less impact than original mobile-friendly-update that is “Mobilegeddon.” The original mobile-friendly update had significant impact on the mobile results.