Network and cable TV don’t revolve around the calendar year, but around programming seasons. These seasons are like school years, in that they overlap two calendar years. So there was a 2017-2018 programming season, right now we’re still in the 2018-2019 season, and in September of this year we’ll start the 2019-2020 season.

Cartoon Network typically doesn’t announce show renewals on an individual basis. Instead, once a year, they announce their entire programming slate for the upcoming TV programming season. That’s when we find out what new shows have been green-lit, and what old ones have been renewed and which haven’t .

Since the movie is slated for release in the fall of this year, a subsequent hypothetical sixth season would likely fall in the upcoming 2019-2020 season, which has not yet had its programming slate released by Cartoon Network.

Judging from the dates of the last five slate releases, we can expect the 2019-2020 programming slate to drop sometime between February 19th and March 30th. Until then, no one should be jumping to any conclusions.