Sky Glass installs updates automatically in background, which is why you’ll occasionally see new features show up or interface changes without any notice. Outside of resetting the device to factory settings, there’s no way to force your Sky Glass TV or Sky Glass Puck to check to see if there’s a new update available for the operating system — they’re rolled out over-the-air, with customers receiving them at different times to prevent Sky’s servers from overloading.
If you’re experiencing an issue with a particular application — Amazon Prime Video or Netflix, for example — or notice one has vanished, you can request Sky Glass check to see if any updates are available and to see if any new services are available. You can do this by heading into Settings, scrolling down to Resets & Updates, and selecting Refresh Apps. This is a bit like deleting and reinstalling an application on your smartphone, fixing most common issues.