Pressure has been mounting for Game of Thrones author George R.R. Martin over the Winds of Winter release date.

Fans of GRRM have noticed that the writer has been unusually silent in the past weeks on social media. The last post he made on Twitter and Facebook was on August 19 before he attended the World Science Fiction Convention in Kansas City. They also observed that Martin has yet to write anything about his three-day appearance at Worldcon. They find it unusual since Martin regularly shares his experiences after every convention.

Moreover, the last time he gave an update about his much-awaited Winds of Winter book on his LiveJournal blog was over a month ago. In his post, GRRM said he “still working on book six.”

This led many to speculate that Martin may probably be feeling the pressure over the constant delay in the Winds of Winter release date. The book is the sixth installment in the epic fantasy series of A Song of Ice and Fire series. Game of Thrones Season 6 was based on Winds of Winter.

Watch a teaser for Game of Thrones Season 7 below.

Although Martin has been upfront in telling that he writes slowly, fans can’t help but press the writer over and over again about Winds of Winter release date.

Meanwhile, DigitalSpy cited one Reddit user stating that another ISBN number has been registered by Penguin publishing allegedly for Winds of Winter.

Reddit user Burnfyre believes that the ISBN is authentic. However, Burnfyre also mentioned that TWOW ISBN 9780002247412 has been registered over a year ago by HarperCollins.  Another Reddit user, BryndenBFish, replied on the thread. He said the old TWOW ISBN 9780002247412 is currently not assigned. He speculates that the new one could be for a special edition.

Nonetheless, the fact remains that fans have been waiting for five long years for the Winds of Winter release date. Now, the least that we can expect is that it would be out before the year ends, probably in early 2017 or before “Game of Thrones” Season 7 premieres.

Stay tuned for more updates on the Winds of Winter release date.