Alongside the redesigned iMac, Apple introduced a new Magic Keyboard with Touch ID for fingerprint authentication, which is useful for quickly logging into macOS or confirming an Apple Pay purchase online.
As first noted by Rene Ritchie and confirmed by MacRumors, the Magic Keyboard with Touch ID is fully compatible with all M1 Macs, including the new iMac, 13-inch MacBook Pro, MacBook Air, and Mac mini. If used with Intel-based Macs or other Bluetooth devices, the Magic Keyboard will still function with the exception of Touch ID.
While the new Magic Keyboard is compatible with all M1 Macs, it will only be available with the new iMac, at least initially. The new iMac can be configured with one of three different Magic Keyboards, including a standard version with Touch ID, a standard version without Touch ID, and an extended version with Touch ID and a numeric keypad.
Apple has made some previously iMac-exclusive accessories available to purchase separately at a later date in the past. When the iMac Pro launched in December 2017, for example, Space Gray versions of the Magic Keyboard, Magic Mouse, and Magic Trackpad were only available with the iMac Pro, but became available separately in March 2018.
The new iMac with the new Magic Keyboard can be ordered starting April 30 and will be available in the second half of May.