Xiaomi
Turn On/Off Auto-Update auf Xiaomi
MIUI can install downloaded system updates by itself, usually overnight while the phone is charging and not in use. This behavior comes from a single toggle buried inside the update settings, and it is easy to miss because it does not sit in the main Settings menu.
When auto-update is active, MIUI downloads the update package in the background and installs it once the device is idle, typically at night. You will not see a confirmation prompt before the install starts. When it is disabled, MIUI still notifies you that an update is available, but nothing happens until you open the update screen and confirm the install yourself.
To change the setting, go to Settings ➔ About phone ➔ MIUI version, then open the menu icon in the top right and tap Update settings. There you find the option Install automatically, which you can switch on or off.
Turning it off makes sense if you need to control exactly when your phone restarts, for example before an important call or while running time-sensitive apps. Turning it on is useful if you rarely check for updates manually and prefer the phone to stay current without extra steps. Either way, the phone still needs to be charging and connected to a stable network for the automatic install to trigger.