Google announced they are replacing the old smartphone crawler user-agent with a new one in order to make it possible for Google to index more smartphone content.
Zhijian He, a smartphone search engineer at Google said that the previous user-agent “made it impossible for Google to index smartphone content of some sites, or for Google to recognize that these sites are smartphone-optimized.”
The new smartphone user-agent crawler will follow robots.txt, robots meta tag, and HTTP header directives for Googlebot instead of Googlebot-Mobile. This will give webmasters more control, but Google said it should only impact less than 0.001% of URLs.
The new user-agent is launched in 3-4 weeks or so.
The new Googlebot for smartphones user-agent:
Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
The Googlebot-Mobile for smartphones user-agent we will be retiring soon:
Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25 (compatible; Googlebot-Mobile/2.1; +http://www.google.com/bot.html)