When a carrier setting update is available, you'll be prompted to install it. If your carrier releases a mandatory update, you'll see an OK button instead of an Update button to let you know that the update was downloaded and installed.

You can manually check for and install a carrier settings update with these steps:

Make sure your device is connected to a Wi-Fi or cellular network. Tap Settings > General > About. If an update is available, you'll see an option to update your carrier settings.

To see the version of carrier settings on your device, tap Settings > General > About and look next to Carrier. To see additional carrier information, tap the version number.

If you insert a new SIM card into your iPhone or iPad, you need to download the carrier settings for your new carrier.