Last night, Apple has released the very first update to its new iOS 11 mobile operating system iOS 11.0.1, it is available on all compatible iPhone, iPad and iPod Touch. It has the build number 15A402, except for iPhone 8 and 8 Plus (build 15A403).
As it did with minor updates to iOS 10, Apple did not share a changelog with iOS 11.0.1. However, she posted a new page on her support explaining that this update fixes a bug that prevented users from sending emails from their Outlook.com, Microsoft Exchange or Office 365 account.
To download and install iOS 11.0.1 on your device, just go to Settings> General> Software update and follow the instructions on the screen. For information, it weighs a little less than 300 MB on an iPhone 7. As a reminder, the final version of iOS 11 for the general public was released on September 19, after 10 beta versions.