How do I update my iPhone 6 Plus beyond iOS 12.5.7 to download Apps?

You cannot update an iPhone 6 Plus to iOS 13 or higher.

For the iPhone 6 Plus, which Apple released over ten years ago, which originally ran iOS 8, and which has only 1 GB of RAM, iOS 12 is the end of the line.

If you need to run apps that require more recent versions of iOS, it is time to replace that iPhone 6 Plus, preferably with an iPhone that is compatible with iOS 18 and also with 5G cellular phone service.

An iPhone 6/6 plus can't be updated beyond 12.5.7, it doesn't have the hardware required to run anything higher.

If you need a higher iOS version, you will have to purchase a newer phone.

• If you have an iPhone 5S or 6/6plus, the highest you can update to is 12.5.7

• If you have an iPhone 6S through 7, or SE 1st generation, you can update to 15.8.3

• If you have an iPhone 8 or X, you can update to 16.7.10

• If you have an iPhone SE (2nd generation or later), or XR through 16, you can update to 18.2.1

This may help --> Apps that require higher iOS versions than your device can be updated to... - Apple Community