Google announced on the Google Webmaster blog that on April 18, 2016, they will be updating their user-agent for the smartphone Googlebot crawler. The user-agent will change from an iPhone user-agent to an Android user-agent, but it should have no impact on 99% of all web sites, says Google.
Here is the new Googlebot smartphone user-agent that kicks in on April 18, 2016:
Mozilla/5.0 (Linux; Android 6.0.1; Nexus 5X Build/MMB29P) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.96 Mobile Safari/537.36 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
Here is the current smartphone user-agent for Googlebot that we have today:
Mozilla/5.0 (iPhone; CPU iPhone OS 8_3 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Version/8.0 Mobile/12F70 Safari/600.1.4 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
The main difference you can see here is that Google is replacing the Apple iPhone and Safari string from the user-agent and replacing it with Android and Chrome.
Google said they are making this change so that their “renderer can better understand pages that use newer web technologies.” Google added that as the web evolved they decided to change the “user-agent string indicates that that it is becoming more similar to Chrome than Safari.” Google said their “evaluation suggests that this user-agent change should have no effect on 99% of sites.”
To ensure your site won’t be impacted by this change, use the Fetch and Render Tool in the Google Search Console.