I want to update my iPhone 6s

Hi,

If you can't update to iOS 15 are you sure you have an iPhone 6s?

Are you following the steps correctly?

Here's two different ways to get the highest iOS that your phone will support onto your phone.

Update your iPhone, iPad, or iPod touch wirelessly. Click here --> Update your iPhone or iPad - Apple Support

Update your iPhone, iPad, or iPod touch with the Finder on a Mac computer --> Update your iPhone, iPad, or iPod touch with the Finder - Apple Support

If you see an error when you update or restore your iPhone, iPad, or iPod, click here --> If you see an error when you update or restore your iPhone, iPad, or iPod - Apple Support

If your iPhone, iPad or iPod touch won’t update - "You might be unable to update your iPhone, iPad, or iPod touch wirelessly — or over the air — for one of these reasons", with more detail in this link. --> If your iPhone or iPad won't update - Apple Support

" Not enough available storage space on your device

Downloading the update takes a long time

Unable to reach the update server

The update doesn't complete"

Read the article "If you need more space for an update" Click here --> If you need more space for an update on your iPhone, iPad, or iPod touch - Apple Support

Things to try:

Plug your device into your computer to update using your computer.

Delete content from your device and try to update again.

Manage the storage on your device with recommendations.

If you can't update or restore your iPhone, iPad, or iPod touch - You can put your iOS device into recovery mode, then restore it using Music/iTunes.

If you can't update or restore your iPhone or iPod touch - Apple Support

Exactly what happens when you attempt to update?

Any error messages?

What is the existing version of iOS?

By the way I have requested your topic be moved to the iPhone forum. That 's where all topics about iOS updating should be located. ;-)