I can’t up date later iso 15

What happens when you try? See if this helps: https://support.apple.com/en-us/HT201263

What happens when you attempt to update?

Any error messages?

What is the existing version of iOS?

kasim112 Said:

"I can’t up date Iso 15"

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Why the Error?: There is an issue connecting to Apple's servers.

To Check for Updates:

Use a Computer and Ethernet:

Start with attempting an update through use of a computer. If you cannot use Wi-Fi, then use Ethernet.  Go Here: Update your iPhone Using a Computer - User Tip. On the computer, you would connect it through Ethernet, going directly into your router. For a Mac (or PC) that does not have Ethernet, this would be the adapter to use: Belkin USB-C to Gigabit Ethernet Adapter - Apple. If you get the same error, the model is likely just not compatible.