On which device ?

Lol all the battery talks going on.
Come on. U can't really compare how powerful your battery is depending on how long it lasts.
I can do basic browsing, whatsapp, wechat, fb and other social media shit and get thru a whole day with battery still remaining at the end.
I can also kill my battery by gaming on asphalt for about 2-3 hours. Or go from 100 to 0 in 1.5 hours by playing the Sims City game.
Point is, it's all about usage habits. If you stress your usage on certain apps, battery life will definitely take a hit.
iOS versions barely changes shit to battery life. It's your usage habits and app updates that affects the battery life. I've been using the iPhone since the first one and never had I once thought "oh cool, battery life has been prolonged over the software update". If u need more power just get a power bank. Or be a wall hugger. Or get an android. iPhones were never known for good battery lives.
Ok bye.