software to be updated

You need an iPhone 8 or a newer model to update to iOS version 16.3.1 (latest iOS version).

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Make sure that your iPhone is setup to meet the following requirements before you attempt to update the iOS version over a Wi-Fi Network. Open Settings ➡️ General ➡️ Software Update: If there is an update available for your iPhone then it will be listed here. Follow the on-screen instructions to download and update your iPhone. 

• Your iPhone must have a fast Wi-Fi connection; you cannot update over cellular data or a cellular hotspot
• Ensure that you do not have a beta profile installed from a previous version
• The iPhone can not be in Low Power mode
• The battery state of charge must be above 50%
• Your iPhone must have at least 8GB or more free storage space
• Your iPhone cannot be connected through VPN
• You should leave the phone plugged in until it finishes updating, both to assure that it remains above 50% and to keep Wi-Fi enabled (Wi-Fi turns off when the phone sleeps if not connected to power).

Axel F.

Turn on automatic updates

Go to Settings > General > Software Update.

Tap Automatic Updates, then turn on Download iOS Updates.

Turn on Install iOS Updates. Your device will automatically update to the latest version of iOS or iPadOS. Some updates might need to be installed manually

Update iOS on iPhone – Apple Support (UK)