Macworld’s Serenity Caldwell noticed a change in the wording that lists software requirements for iBooks Author books on iTunes, and she thinks that may suggest iPhone support is coming next week:

To my mind, it’s likely that we’ll see iBooks Author support on the iPhone when iOS 7 is released. The groundwork, after all, has already been laid. As I mentioned in my critique of the program last year, iBooks Author already has a potentially viable option for iPhone and iPod touch users—its reflowable portrait mode. In it, interactive elements float alongside the text, which itself can be resized by the reader. In addition, current iPhone models (and any that might get announced next week) will have more than enough power to display videos and other interactive content.

I submitted a book made with iBooks Author to Apple a few days ago, and I completely agree with Serenity. Recent iPhone models (with Retina displays and taller screens) could work well with iBooks Author’s portrait mode (where font size can be adjusted) and it seems strange that Apple still hasn’t done this. I hope that we’ll see iPhone support for iBooks Author books next week, as that would lead to a terrific boost in addressable audience for publishers.