Google announced that they are updating the name for the Googlebot-Mobile user-agent and that if you do any special directives for that user-agent, you should be aware.
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)
Why the change?
Google said 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."
Google also added that the "new Googlebot for smartphones crawler will follow robots.txt, robots meta tag, and HTTP header directives for Googlebot instead of Googlebot-Mobile."
Pierre Far from Google said on Google+:
On a personal note, I love this change on philosophical grounds: We're quickly moving to a world where there isn't a "mobile web" or a "tablet web" or a "desktop web". Instead there is just one web that happens to be accessed from phones, tablets, or desktops.
Forum discussion at Google+.