It’s a massive week for Apple with the US technology giant not only unleashing new AirPods, Apple Wathches and iPhones but also its latest and great iOS operating system. iOS 18 was released last night and is free to download if you own a recently released device such as the iPhone15, iPhone 14, iPhone 11 and even the iPhone XS. It comes packed with features including improved ways to message, new Photos and Password apps plus there’s now the option to fully customise the home screen and even change the colour of your applications.

It’s a mighty release from Apple and you can read our top five iOS 18 features here. However, if you’ve downloaded and installed it on your devices be warned.

Whenever Apple releases its yearly iOS updates there are often moans and groans from users about battery life.

Previous releases have seen iPhone fans rushing to social media to vent their frustration about the power reducing much faster than normal.

We’ll have to wait and see if iOS 18 causes the same problems this year but if your iPhone’s battery indicator suddenly starts flashing red after installing iOS 18 the advice is not to panic.

READ MORE: AirPods 4 review: Apple just gave you a very tough choice to make

It’s a well-known fact that Apple’s major iOS updates will typically drain things much faster during the first few days of use.

So why does this happen and how can you stop it?

First off, there’s the simple fact that you are probably using the phone more as you try out all the shiny new features and start tinkering with the new home screen app tints. Of course, the longer you have the display powered up the faster things will run flat.

Another factor is that you are likely to be installing a lot more updates from the App Store. That’s because dozens of developers have already started to roll out crucial upgrades to their software in order to take advantage of the new features in iOS 18. If you have automatic updates switched on, these will all be chugging along in the background without you even knowing.

Finally, there will be a lot going on behind the scenes to make sure your iPhone is optimised for this new release.

Your iPhone will now be re-indexing data including contacts and apps plus everything that can be searched using Spotlight on the iPhone needs to be re-categorised and sorted by the operating system.

Unlike some rivals, Apple insists these complicated processes are carried out on device because it does not want the privacy implications associated with sending the data to the cloud.

This is all happening in the background following the update, battery life will suffer and it can take a day or two before things get back to normal.

So, do not worry. Your iPhone should be back to full power very soon. Just carry a charger for the next few days if you're worried about things running flat