1. Starting April 21, we will be expanding our use of mobile-friendliness as a ranking signal, meaning more #mobilefriendly sites in search results.
2. Starting today, we will begin to use information from indexed apps as a factor in ranking for signed-in users who have the app installed.

Get the full details on their blog: http://googlewebmastercentral.blogspot.com/2015/02/finding-more-mobile-friendly-search.html

Now you should check if your site is mobile-friendly or not.

Here is the link to check: https://www.google.com/webmasters/tools/mobile-friendly

If you get the green bar with the message: Awesome! This page is mobile-friendly. like we did a test with our Sentient template

If you get the red bar with the message: Not mobile-friendly

then you ought to fix all issues pointed out by Google or change your current theme to a responsive one. Either a free responsive theme by Weebly or a premium responsive Weebly template from Baamboo Studio is fine.

Since this update will have more of an impact on Google’s search results than the Google Panda update and the Google Penguin update did, you should act fast to avoid losing visitors and customers.