'The Winds of Winter' release date news, updates: Excerpt included in Apple's Enhanced Edition of 'A Game of Thrones' for iBooks

An extract from the upcoming "The Winds of Winter," the sixth novel in George R.R. Martin's bestselling "A Song of Ice and Fire" saga, is included in a new digital edition of "A Game of Thrones" that is being offered exclusively on iBooks.

"A Game of Thrones: Enhanced Edition" is being launched in celebration of the 20th anniversary of the novel. It will allow fans of both the novel and of the HBO series it is based on to have an interactive experience of the world it created. The Enhanced Edition comes with lots of interactive content, including character maps, the lineages of the great houses, detailed annotations, and a new appendix. Clicking on a name or a house in the new digital version will reportedly allow readers to track a character's journey or a great house's history. In addition, the Enhanced Edition contains an excerpt from the twice-delayed "The Winds of Winter," the much-anticipated next installment in Martin's epic fantasy series.

The Guardian reports that HarperCollins has confirmed that the excerpt included in the new digital edition of "A Game of Thrones" was briefly published on the author's website. The publishing house also reportedly said that the extract can now only be found in Apple's new edition of "A Game of Thrones."

Based on this, The Verge suggests that the excerpt that was included in "A Game of Thrones: Enhanced Edition" could be the Theon Greyjoy chapter that Martin shared on his website in December 2011. The chapter is still up on Reddit.

"We're now entering a new period in the history of publishing," Martin recently said, announcing the new digital edition of his 20-year-old novel. "The digital book gives readers the ability to experience all this rich secondary material that had not been possible before. These enhanced editions, available only on iBooks, include sigils and family trees and glossaries. Anything that confuses you, anything you want to know more about, it's right there at your fingertips. It's an amazing next step in the world of books."

The first book of "A Game of Thrones: Enhanced Edition" is already available for purchase on iBooks. It costs $8.99. The next four books will be released in the next few months. Preorders are already being accepted on iBooks.