Update to iOS 12.7.5

The correct update version is iOS 12.5.7 for your iPhone 6 Plus.

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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
• 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.

Last87 Said:

"Update to iOS 12.7.5: Download software"

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Do you mean "iOS 12.5.7"?

Updating iPhone 6 Plus Past iOS 12.5.7:

This is not an Option:

You iPhone model (6 Plus) is incompatible with iOS13 and/or iOS14  and/or iOS15, and/or iOS16. This is because your iPhone model (6 Plus)does not meet the hardware requirements for this iOS version(s). So, you may need to get a SIM card made for iOS12 and/or before.

For future reference...

Troubleshooting iPhone Storage:

Internal storage cannot be upgraded. It is what it is. So, the maximum internal storage capacity never increases, even if you upgraded your iCloud plan. Learn More here: What's the Difference Between Device Storage and iCloud Storage? Apple Support. So, you'll just have to clear space, and then perform the upgrade.

So, what to do:

Clear Space:

Try clearing internal storage though use of the following:

What Space to Clear:

A. Clear Temporary Internet Files:

Clear your Temporary Internet Files(Cookies & Cache) of Safari:

• Cookies perform remembrance of certain site-entered data.
• Cache keeps a snapshot of the last time you visited a site.
• Go Here: Clear the History and Cookies from Safari on your iPhone, iPad, or iPod Touch - Apple Support

And...



B. Clean TV and Music Libraries:

Remove all unneeded files from your TV and Music Libraries. Full-Movies take up 2-4GB typically, and a bunch of those would take up a load of storage, ideally. So, if you have any movies that are not needed, then delete them.

And...

C. "Other" being the Culprit:

Use this Link: How to Check the Storage on your iPhone, iPad, and iPod touch - Apple Support. The storage named "Other" is the grey bar. So, to clear that, this is what to perform: Clear Other storage on your iPhone or iPad - Apple Support