Apple's own iBook reveals iPad Air 2 & iPad mini 3, both with Touch ID

The devices aren't featured in the iBook download itself, but can be found within the screenshots for the digital book, entitled "iPad User Guide for iOS 8." The very first screenshot displayed on the download page plainly names and shows both an iPad mini 3 and iPad Air 2, both featuring Touch ID fingerprint sensors.

The book was published by Apple itself back on Sept. 17, and does not appear to have yet been updated to iOS 8.1 as the screenshot depicts. It's unclear exactly when the screenshots were updated with the error spotted Wednesday.

Further information within the guide suggests the iPad Air 2 camera will gain a new burst mode for taking pictures with the rear iSight camera.

The hardware on the devices appears largely the same, with a Lightning connector and speakers on the bottom, and the screen sleep/wake button remaining on the upper right side.

Though the accidental leak is uncharacteristic for Apple, none of the details shown in the iBook screenshot are unexpected. Rumors have persisted for months claiming that Apple is set to showcase new iPad models featuring Touch ID for this fall's update.

Apple is also expected to unveil a new 27-inch iMac with a 5K-resolution Retina display at the event, which will be held at its corporate campus in Cupertino, Calif. The keynote is scheduled to begin at 10 a.m. Pacific, 1 p.m. Eastern, and AppleInsider will be there with full, live coverage of the proceedings.

The updated iOS 8.1 user manual also hints that Apple could announce the release of the mobile operating system update. iOS 8.1 is expected to enable the new Apple Pay feature for iPhone 6 and iPhone 6 Plus users.