Two weeks since the original release, and one week after the last minor update, Apple has released iOS 11.0.2 with rectification of crackling sounds during calls on the iPhone 8 and iPhone 8 Plus, and other assorted fixes.
Apple notes that in addition to the crackling sound fix, Apple has also addressed an issue that could cause some photos to be hidden, and another where attachments in S/MIME encrypted emails would not open.
Security fixes have been applied as well, but Apple has not as of yet detailed them.
The build number is 15A421. The previous build was 15A402 for the iPhone and iPad.
As with previous revisions, iOS 11 is compatible with the iPhone 5s and newer, the iPad 2 and up, the iPad Air and newer, and all iPad Pros. It is also compatible with the sixth-generation iPod touch.
The update on an iPhone SE is 276.9MB in size. On a first generation iPad Pro it is 297.1MB.