iTunes will not let me update to iOS 10
I am trying to upgrade my iPhone 6S to iOS 10 via iTunes. However, when I choose the "Update" button in iTunes on the iPhone screen it tells me that "This version of iTunes (12.4.3) is the current version." The text above the "Update" button does say that "A newer version of the iPhone software is available..."
It appears that the update is looking at iTunes and not my iPhone. Any ideas on how to correct this?
Running MacOS 10.8.5 on MacBook Air.