Pre-orders and previews begin April 10, launches April 24.
iCloud Keychain Removed in iOS 7 GM
iCloud Keychain is also newly tagged as "Coming soon" on Apple's iOS 7 feature page and while it is unclear why it has been removed from the GM, it is likely that Apple has chosen to provide the feature alongside OS X Mavericks, which is slated to be released later this year.
First introduced at WWDC, iCloud Keychain is Apple’s new cross-device password manager, designed to share and store passwords across all of Apple’s products running iOS 7 and OS X Mavericks. In addition to passwords, iCloud Keychain also stores website logins, credit card information, and Wi-Fi networks.
While Mavericks will not be available until later in the fall, iOS 7 will be released to the public on September 18, ahead of the release of both the iPhone 5s and the iPhone 5c.