Following Sitemaps.org 's recommendation to increase the file size limit of Sitemap index files, Google this morning tweeted the change of increasing the Sitemaps files from 10MB to 50MB.
Bing just yesterday announced the change as well.
The change applies to only the size of the index files, but the 50,000 URL limit per Sitemaps file is still valid i.e. you can still only have up to 50,000 URLs in a single Sitemap file.
We've updated the Sitemaps protocol with Bing! Sitemaps & indexes can be considerably larger now. More at https://t.co/uygpuywUEh— Google Webmasters (@googlewmc) November 30, 2016
Also, Google has also dropped support for feature phone crawler and crawl error report in Search Console. However,
In a post Google said, that "most websites don't serve feature-phone content in WAP/WML anymore and thus wouldn't be affected."
If your website has been providing feature-phone content through dynamic serving based on the user-agent, you need to add a "handheld" link annotations on your desktop and smartphone pages for dynamic serving contents to limited mobile-device "feature phones".
Once this self-referential alternate URL link for handheld devices is added to pages, Google will continue to show feature-phone URLs in search as it recognize them, "and when they're appropriate for users."
Further, this change won't impact how Google crawls or indexes smartphone content, Google adds. Adding, "this is a change from our previous guidance of only using the "vary: user-agent" HTTP header."
Since, Google is no longer crawling feature-phone content, they have retired the feature-phone Googlebot. "We won't be using the feature-phone user-agents for crawling for search going forward," Google said.
With the limited mobile devices user-agents ends, Google is also 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," added Google.
For more information, you can see this updated documentation on making feature-phone pages accordingly.