Unable to activate an update is required to activate your iphone
Unable to activate. An update is required to activate your iPhone.
iPhone 6 Plus
Question marked as
Top-ranking reply
If you see "Software update is required to connect to your iOS device" on your iPhone, iPad, or iPod touch - https://support.apple.com/HT208831
"When you connect your iPhone, iPad, or iPod touch to a Mac with macOS 10.11 or later, you might need to update the software on your Mac in order for it to recognize your iOS device. Learn what to do."
This is an Apple Recommended solution for this problem even though it appears at first it is not the once you need: https://discussions.apple.com/thread/8552696