Microsoft Windows 10 Mobile cumulative update build 10586.212 has been spotted. The cumulative update is currently being tested internally. Recently We had spotted cumulative update build 10586.200 for both Windows 10 PC and Mobile.
The new cumulative update may fix a bug that involved closing an app that was launched from the Apps List. Currently, closing an app launched from the Apps List would cause the background to essentially un-dim itself, making it hard to read text when using a light background. This issue is fixed in the latest Redstone builds and is now fixed in the upcoming patch for current branch users.
Microsoft is mainly focused on the upcoming Anniversary Update for Windows 10, which will be launching for Windows 10 Mobile users this summer alongside the desktop release. The Anniversary Update brings changes to Cortana, Notifications and Microsoft Edge. In the meantime, however, current branch users can expect more cumulative updates that fix more bugs.