If syncing to iTunes 11.4 is important, DO NOT update to iOS 10. Even if you do it over wifi, your iDevice will no longer sync to iTunes 11.4. When you try to hook it up, you will get the following alert on your Mac:
iTunes could not connect to the iPad because an invalid response was received from the device.
Meanwhile, you will get the following alert on your iDevice:
Trust This Computer?
Your settings and data will be accessible from this computer when connected.
Clicking "Trust" doesn't do anything. Your iDevice will never sync with iTunes 11.4 again.