Starting from Android
6 Marshmallow, Doze mode helps preserve battery life by putting your phone in a deep sleep state when you're not using it for an extended period of time.
When your phone is not charging, the screen is off, and your phone has not been moved for a period of time—such as overnight—it automatically goes into Doze mode.
- Notifications don't exit your phone from Doze mode. You'll get notifications after one of the above occurs and exits your phone from Doze mode.
- If you're using another app for MMS, you may not receive MMS messages while in Doze mode. You can use the Battery optimization setting to turn off battery optimization for your app. See the user guide or how-tos for details on this setting.