Update your iPhone. It appears that you may have a previously installed Beta profile. Remove that beta profile and try to update your iPhone again. Open Settings ➡️ General ➡️ VPN & Device Management ➡️ Configuration Profile: Tap on the existing profile and then choose Remove Profile.
Read The Following:
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 6GB 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.