It corrects an issue for some iPhone 7 and iPhone 7 Plus devices, where audio and haptic feedback wasn't working. Recently developer Felix Krause (via MacRumors) posted proof of concept of a phishing attack that iOS developers could use to gain the user's Apple ID and password. Today, iOS 11.0.3 was released, apparently for the sole objective of exterminating a couple of bugs that were affecting users of the Apple iPhone 6s, the Apple iPhone 7 and Apple iPhone 7 Plus. The static noise was heard when users were on a phone call or using FaceTime. iOS 11's previous update, iOS 11.0.1, was released two weeks ago and included fixes to bug issues. Apple went so far as to include a reminder to use Apple-certified screen fix services in the update notes, something I haven't seen before. "Non-genuine replacement displays may have compromised visual quality and may fail to work correctly".
iOS 11.0.3 comes about a month after the official rollout of iOS 11, itself a major update to the Apple operating system. That's accompanied by a passive-aggressive note warning against repairs made with non-Apple parts. As the name suggests, it's the third update since iOS 11 was released for all customers on September 19th. As such, beyond the bug fixes, there aren't any remarkable, user-facing changes to the iOS 11 experience in these last few updates.
iPhone and iPad users have been warned of a new type of phishing scam that tricks you into giving away your Apple ID. As Krause says, "Just ask your users politely, they'll probably just hand over their credentials, as they're trained to do so".
To obtain the update, simply go to Settings General Software Update on your iOS device.