We are continually improving on the Control Center experience. To do this we will occasionally push a software update to your device firmware. Your unit will automatically check for updates from time to time, and may ask you if you want to update your unit:
You can either choose to update immediately, or to dismiss the update. When you start the update, Control Center will first download the update before beginning the installation process. This could take up to 10 minutes, and your unit may restart several times during this process.
If you dismiss the update, you will be asked during the next startup to update your system.
You can also manually check for updates, by navigating to Settings > About, and selecting Firmware Version - Check for Updates: