Change the date on iPhone, iPad
On your iPhone or iPad, go to Settings > General > Date & Time and turn off Set Automatically. Then set the date on your device to any time before December 14, 2023.“Set Automatically” in Date & Time settings is grayed out? Here’s how to fix it →
From your device, tap the button below to download the Block OTA profile. Your device will notify you when the profile has been downloaded. Open Settings, tap the profile and follow the onscreen instructions to allow installation.
Restart your device
Don't forget to restart your device after installing the profile so any changes can be applied.
To check if the profile is active on your device, go to Settings > General > Software Update. If it displays "iOS is up to date," you have successfully blocked updates.