Sony Mobile has rolled out a new firmware update with the build number 23.5.A.1.291 for Xperia Z2 series and Xperia Z3 series. So this will replace the previous 23.5.A.0.575 build from the new build 23.5.A.1.291. Currently this new update is live for Xperia Z3 D6603 and Xperia Z2 D6503. It will arrive to other variants shortly. Sony has re introduced the stamina mode in this. But unfortunately this too looks like the renamed version of the stock android's battery saver. Some users claim that this update will fix the multi tasking bugs that were available on the previous build. So if you have installed this share your thoughts about the update.