No thank you

What happens when you try?

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.5

• If you have an iPhone 6S through 11, you can update to 14.8.1 or 15.1

• If you have an iPhone 12 or 13 you can update to 15.1.1

Update your iPhone, iPad, or iPod touch -

https://support.apple.com/en-us/HT204204

Can you post a screenshot of the whole screen, it could reveal why you aren't able to update.

Make sure you:

• Are using a WiFi connection (not a hotspot).

• Have your battery charged at least 50%. Better yet, keep it plugged in during the update.

• Are not using a VPN connection.

• Do not have power save mode turned on.

• Do not have a beta version installed.

• You have at least 6 gigs of storage available.

You can also check out this article for help -

If your iPhone, iPad or iPod touch won’t update

https://support.apple.com/en-gb/HT201435

Kirollos9 Said:

"No thank you: this phone won’t let me update"

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What’s the update? What’s the error? Let's say it is compatible. For the sake of it, try the following…

Use a Computer and Ethernet:

Start with attempting an update through use of a computer. But this time, user 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

Your signature suggests you have an iPhone 6s, which is currently running iOS 11. Let's find out what you actually have:

Settings > General > About > Model (tap it twice) and Version (don't tap it) - Just report back

There is no need to use Ethernet when updating with a computer. Wi-Fi is just fine. As most users don’t even know what Ethernet is anymore this is an added complication, as it requires buying a cable, locating the computer near enough to the router to connect the cable, and, with most computers, buying an Ethernet to USB adapter. All of which is unnecessary effort and expense.