You can update an iPhone 4

Update iOS on iPhone

If you update to the latest version of iOS, your data and settings will not be affected.

It is advisable to set up the iPhone in such a way that the data is automatically backed up before an update. Alternatively, you can manually back up your data before starting the update.

Update iPhone automatically

If you didn't turn on automatic updates when you first set up your iPhone, do the following:

  1. Select "Settings" > "General"> "Software update".

  2. Tap Customize Automatic Updates (or Automatic Updates). You can choose to have updates downloaded and installed automatically.

If an update is available, iPhone will charge it and install it overnight while it is charging and connected to Wi-Fi. You will receive a message to this effect before the installation.

Update iPhone manually

You can check at any time whether a software update is available and install it if necessary.

Select "Settings" > "General"> "Software update".

The screen shows the currently installed iOS version and whether an update is available.

To turn off automatic updates, choose Settings> General> Software Update> Customize Automatic Updates (or Automatic Updates).

Update software using your computer

  1. Connect the iPhone and your computer with a cable.

  2. Do one of the following:

    • In the Finder sidebar on your Mac: Select your iPhone, then click General at the top of the window.

      To update your iPhone using the Finder, macOS 10.15 or later is required. With older versions of macOS, you can use iTunes to update your iPhone.

    • In the "iTunes" app on your Windows PC: In the iTunes window, click the iPhone button in the upper left corner, then click Overview.

  3. Click on "Check for update".

  4. Click Update to install an available update.

For more information, see Update to iOS 13 or iPadOS and the Apple Support article Unable to update or restore your iPhone, iPad, or iPod touch.