Back in October 2012 when Microsoft rolled out Windows 8, the company also introduced a new software update system, improving every single installed Metro app through the Windows Store.
It appears that Windows 8.1 / Blue might bring a new change, as the company could use the same Windows Update feature to roll out bug fixes and feature improvements to users' Metro apps.
A post on BetaArchive and spotted by WinBeta reveals that Microsoft has already refreshed the Movie Moments app available in the leaked build of Blue through Windows Update, which could be an indication that Microsoft might be thinking to update all Metro apps via this built-in feature.
On the other hand, using Windows Update may be Microsoft's only option to bring new features in Movie Moments at this point since the app isn't yet available in the Windows Store.
Of course, nothing is confirmed for the time being, so we're still waiting for an official word on this from the Softies.