Stamina Mode is a feature that used to be offered on Sony handsets. When the feature was activated, unauthorized applications couldn’t run in the background and sync with servers, providing a significant chunk of battery and data savings to the user. Since it was interfering with the Doze mode in Android 6.0 Marshmallow, Sony removed it from the early Marshmallow builds for its devices, but it has found a way to bring it back into the fold.
Sony has confirmed that it’s going to bring back Stamina Mode, it’s going to be released first in the Xperia Beta Program, where the feature will be tested on beta builds before it’s decided that no issues exist and it can then go ahead with the public release.
The company appears to have found a way to ensure that Doze mode and Stamina Mode can coexist on the same device without tripping over each other. It’s possible that Sony might have made some changes to how Stamina Mode works in Marshmallow.
Many users prefer Stamina Mode because it provides more options and it works constantly as opposed to Doze mode which is only useful when the device is stationary.
Sony isn’t confirming how long it’s going to take before Stamina Mode starts showing up in beta Marshmallow builds for its devices but it shouldn’t take too long for it to arrive. The Xperia Beta Program is currently limited to users in a handful of European countries and provides builds for the company’s recent Z series devices.