When can I download / install iOS 12?
Apple released iOS 12 on Monday, September 17, 2018.
To update your iPhone, Pad or iPod touch, first make a backup of your device with iTunes or iCloud. iOS can be updated over-the-air (OTA) under Settings -> General -> Software Update, or on a computer using iTunes.Click here for a list of devices compatible with iOS 12.
iOS 12 includes many speed and stability optimizations, in addition to Screen Time, improved AR capabilities, and Shortcuts.