Link to the full article below, but there's one part that interested me:
In this remainder of this season, a flashback episode will encompass much of the show's run to date. Harmon gave few clues as to what else to expect, save an assurance that some familiar faces will be returning and some are probably leaving.
"I'm hesitant to answer the question only because I don't know what I can or can't say," he said. "But, listen, it's all headed somewhere."