Limited mobile devices, "feature-phones", require a special form of markup or a transcoder for web content. Most websites don't provide feature-phone-compatible content in WAP/WML any more. Given these developments, we've made changes in how we crawl feature-phone content (note: these changes don't affect smartphone content):
1. We've retired the feature-phone Googlebot
We won't be using the feature-phone user-agents for crawling for search going forward.
2. Use "handheld" link annotations for dynamic serving of feature-phone content.
Some sites provide content for feature-phones through dynamic serving, based on the user's user-agent. To understand this configuration, make sure your desktop and smartphone pages have a self-referential alternate URL link for handheld (feature-phone) devices:
<link rel="alternate" media="handheld" href="[current page URL]" />
This is a change from our previous guidance of only using the "vary: user-agent" HTTP header. We've updated our documentation on making feature-phone pages accordingly. We hope adding this link element is possible on your side, and thank you for your help in this regard. We'll continue to show feature-phone URLs in search when we can recognize them, and when they're appropriate for users.
3. We're retiring feature-phone tools in Search Console
Without the feature-phone Googlebot, special sitemaps extensions for feature-phone, the Fetch as Google feature-phone options, and feature-phone crawl errors are no longer needed. We continue to support sitemaps and other sitemaps extensions (such as for videos or Google News), as well as the other Fetch as Google options in Search Console.
We've worked to make these changes as minimal as possible. Most websites don't serve feature-phone content, and wouldn't be affected. If your site has been providing feature-phone content, we thank you for your help in bringing the Internet to feature-phone users worldwide!
For any questions, feel free to drop by our Webmaster Help Forums!