Microsoft is updating all of its built-in Windows 8.1 apps ahead of the operating system's release later today. Updates are available immediately in the Windows Store for those using the final version of Windows 8.1, and they appear to be largely performance-related changes. Microsoft's Xbox Music app now launches a lot faster and includes improvements to the various Snap Views within the app. Mail, Calendar, and People have also been updated, but there's no significant visual changes to report.

Although Microsoft's Games app has also been updated, the application still uses the old user interface instead of the Xbox One-like interface of the Xbox Music and Xbox Video apps. Optional apps like Movie Moments, SmartGlass, and Fresh Paint have also been updated. Movie Moments has been slightly redesigned, but it still contains the basic movie making features. Fresh Paint has been overhauled with watercolor support and a new user interface in preparation for Windows 8.1. All of the built-in app updates are available immediately in the Windows Store for Windows 8.1 users. Microsoft is planning to release the Windows 8.1 update to existing Windows 8 users at 7AM ET this morning.