They have revealed that GOT will end with Seasons 7 and 8. While Season 7’s episode count was set at seven last summer, before it went into production, the length of GOT’s final installment had been in flux. Benioff and Weiss had said that they were considering a 6-episode final season but that was not set in stone. As of now, there still is no a firm episode count.
“We are talking about it,’ HBO president of programming Casey Bloys told Deadline at TCA. There is no rush. Seasons 7 and 8 won’t be filmed back-to-back, so there is time to lock that in. While renewal for GOT has never been in doubt, it traditionally has been done around the previous season premiere.