If you think your iPhone's battery isn't performing well, despite keeping up with software updates, have a look in Settings > Battery.
If you see that "Your iPhone battery may need to be serviced", don't hesitate and come to see us. We will swap batteries in a day or even while you wait, for £70, and in some cases your repair might be covered by Apple.
Please note this isn't a safety issue, it's just to let you know that your battery may need to be replaced. You can continue to use your iPhone until you have your battery checked.