Microsoft has now pushed out a bunch of updates for Windows 8.1 core apps, which can be installed on the RTM of Windows 8.1
From Neowin:
From Neowin:
To get the updates, open the Windows Store app > Charms menu > select App Updates, and then check for updates. The 19 updates include enhancements and fixes made from the original release of Windows 8.1.App Updates now available for Windows 8.1
Among the updates are also Windows 8.1 exclusive apps they are:
Windows Calculator
Windows Scan
Windows Sound Recorder
Bing Health and Fitness
Windows Help and Tips
Windows Alarms
Windows Reading List