Whenever you update to a new iOS you need to recalibrate the battery monitor.
You have to charge it to 100%, then let it drain to as low as you can get it before it shuts off (do not plug in device at all during this time...defeats the purpose), then charge it backup keeping it on charge for a good 2 hours "after" it reaches full charge.
Then your battery has had a full charge cycle and is properly calibrated.
Only then can you see if your battery usage has gotten worse since the update.