According to leakster @Ricciolo, Sony Xperia Z5 family of smartphones could receive a decent battery life boost with the upcoming Android 6.0 Marshmallow update, thanks to an ‘improved’ Stamina Mode.
All three Z5 series smartphones – Xperia Z5, Xperia Z5 Compact, and the Xperia Z5 Premium are equipped with impressively large batteries for their size, so the battery life on these devices isn’t currently unimpressive by any means. So, a significantly improved Stamina Mode should help these smartphones deliver even better battery life, possibly on par with the Xperia Z3 and Xperia Z3 Compact from last year.
Sony’s Stamina Mode works similar to other OEM’s battery saving modes, basically turning off connectivity features when not in use and limiting background processes when the screen is turned off.
Sadly, we don’t know when Sony will begin rolling out the Marshmallow update as the company didn’t announce a timeframe when it confirmed the list of Xperia devices eligible for the update recently.