Microsoft today released minor updates for Outlook Groups, Xbox and Store apps in Windows Store.
Outlook Groups app update includes stability fixes to prevent frequent crashes of the app and performance optimizations for DB.
There is no change log available for Xbox app update, so it must be just bug fixes. Recent Xbox app update added several new features. Read about it here.
There is no change log for Store app also. So it must be another bug fix update improving the overall app experience.
You can download these updates from the Windows Store links below.