Apple has released iOS 11.0.3. It can be downloaded for free on eligible devices over-the-air in the Settings app. To access the update, go to Settings --> General --> Software Update.
According to Apple, iOS 11.0.3 fixes an issue where audio and haptic feedback would not work on some iPhone 7 and iPhone 7 Plus devices. It also addresses an issue where touch input was unresponsive on some iPhone 6s displays because “they were not serviced with genuine Apple parts.”