Detailed by The Hollywood Reporter, nothing is set in stone at this time. Speaking about the possibility of shorter seasons, an HBO spokesperson said “Any conversations about the end of Game of Thrones and the number of episodes of future seasons is purely speculative. As is customary, HBO will sit with Dan and David to discuss the details once a decision has been made to go forward with season seven.”
Of course, two shorter seasons could mean viewers won’t have to wait as long to see the final season. Traditionally, Game of Thrones fans have had to wait a full year for each season to be start on HBO. However, this could also be a ploy to retain HBO subscribers for a longer period of time rather than simply broadcasting an extra long 13-episode season. AMC has used this tactic on mulitple occasions, splitting up seasons of major shows like Breaking Bad, Mad Men and The Walking Dead.
The sixth season of Game of Thrones begins on April 24, 2016. This is the first season that will debut before the next book in George R.R. Martin’s fantasy series is actually released. Called The Winds of Winter, it’s likely that HBO subscribers will get to see events of the book happen on screen before fans of the book series get to read about it. At this time, there’s no set release date for The Winds of Winter.