It supposedly only affects SERPs on mobile, and not desktops. But they can change their mind anytime..

It only affects search ranking on mobile devices.

One of the search results thingys with google is mobile friendly added next to your link in the results.

Googles official word is
"As we noted earlier this year, today’s the day we begin globally rolling out our mobile-friendly update. We’re boosting the ranking of mobile-friendly pages on mobile search results."