Update: Fixed:

The compatibility requirements for iBooks Author titles in iTunes have changed, potentially hinting at both the imminent launch of Apple’s upcoming OS X Mavericks and perhaps even iBooks Textbooks for iPhone. As noted by Macworld, Instead of explicitly stating that books require an iPad to view, iTunes now uses the less-precise wording that “you must have an iOS device with iBooks 3.0 or later.” Although textbooks will currently not open on an iPhone, the implication is that the wording has been changed because support for iBooks textbooks on the iPhone is imminent…

Apple changed the wording of iBooks requirements on iTunes again: http://t.co/P3nIaz5dlu

This morning: https://t.co/DJFa2Xywsv

— Federico Viticci (@viticci) September 5, 2013

Changes to iBooks in the near-future are expected as Apple prepares for the launch of iOS 7. With iOS 7’s launch including a focus on app redesigns, it is highly likely that iBooks for iOS will be revamped to drop its currently iconic (and controversial) wooden bookshelf.

More interestingly, the requirements copy now references support for Mavericks, which brings iBooks to the Mac for the first time. This suggests that the release of OS X 10.9 is also imminent. With Mavericks Developer Preview 7 seeming like a near-complete build of the OS, and Apple holding a media event next week, a September launch seems plausible.

The mention of Mavericks means that the change in wording for these books is not some sort of technical glitch, but intentional.

The iTunes Store has a history of heralding new releases of products before their public debut. For instance, in October 2012, in the same ‘Requirements’ section, iTunes mentioned iBooks 3.0 a few days before it was announced.

Today’s change also makes some logical sense. With the iPhone lineup now predominantly consisting of devices with a 4-inch display, it will be easier to scale down iPad-sized experiences to the phone than when most iPhones had smaller 3.5 inch screens. With the iPhone 5C, Apple will even be bringing the 4-inch display to more iPhones.

When iBooks Author was announced, the iPad-only limitation for interactive books was expected to be temporary. It now seems like, finally, the assumption will become reality.