Error message unable to install iOS update 15.1 on iPhone 7

To update all of these requirements must be met:

• You need at least 6 GB of free storage
• You must be connected to a Wi-Fi network (and not a personal hotspot) unless it is an iPhone 12 or 13 series with an active 5G network connection
• The phone must be charged to at least 50%, and preferably plugged in so it stays above 50% during the update
• The phone must not be in Low Power Mode
• The phone must not be connected through VPN
• The phone cannot be in Airplane mode

Hello rachelalberti6,

Thanks for using Apple Support Communities! It looks like you're having issues with updating your iPhone 7 Plus, and we'd like to help.

This article has some great troubleshooting steps to get started with:

If you see an error when you update or restore your iPhone, iPad, or iPod

If the error message received is shown in this article, there are specific steps:

iOS update and restore errors

Lastly, this article has recovery steps. Make sure you've got a backup first, as mentioned in the article viewed before posting your question.

How to back up your iPhone, iPad, and iPod touch

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

Take care!