From the home screen, use two fingers to swipe down the Status bar.
Tap the Settings icon.
Note: If only one finger was used to swipe down the Status bar, swipe down again to access the Quick Settings menu.
Scroll to and tap About phone.
Tap System updates.
The device will check for updates.
If an update is available, follow the prompts to download and install it. Otherwise, tap OK.
Your device software is up to date.