[victory_angel]

The characters are coming to a point where they can no longer consider themselves teenagers. Despite the lack of focus on time passing, time does pass in the show and occasionally they do acknowledge it. Such as Kraang Subprime mentioning it's taken a couple of years to get the technodrome (the one that was sent into the bay) up and working again.

This would suggest the Turtles are 17 years old since the Turtles are 15 years old when the series starts and when they defeat the Kraang in Showdown. Two years after that would be 17.

Not to mention the time the Turtles went back in time six months to save the Earth from being destroyed. Just because the Turtles themselves went back in time, it doesn't mean they aged backward with that time. Those six months would still have been with them. And of course, the times that the Turtles had been in Dimension X, Mikey does mention he had been there for several months waiting for his brothers, even though his brothers had a 15-second gap of time.

Typically 18 is when a person is no longer considered a child. This can be hinted at in the moments when Splinter is pointing out to the Turtles that they are coming to the point where they are no longer children.

But Splinter is also Japanese, there is a ceremony in Japan called "Coming of Age Ceremony" Which is an annual ceremony to acknowledge those who have reached adulthood which is around the ages of 19-20. And their are some hints that yes this is likely where the Turtles are age wise.

So if the Turtles are in fact leaning towards their twenties, you can't continue the series with the word "Teenager" in the title.

Ciro himself has also said he can see his vision of the show last five seasons. We have reached five seasons and even if we don't get around to or conclude certain story lines, then there are things that can be covered through a Spin-off, mini-series, or made for TV specials.

For example, there was mention of a Spin off a couple years back, and there was also news of a Spin-Off called to "O'Neil Files". While this Spin-off has spun-off the radar, there has been no word of it being discontinued as far as consideration. It's possible they were waiting for the current TMNT series to come to it's conclusion before they started pushing it.

Another example is the space arc, a lot of the stories were rushed and there was so much potential but we couldn't flesh out the universe because there, of course, was the rush to get the pieces of the "heart of darkness". But then we see the temporal copies of the Turtles, April, and Casey, going into space.
Peter DeCico did give three plausible outcomes for what happened to them.
1. They went back in time and merged with the current Turtles from the alternate time-line.

2. Since their timeline no longer exists they disappeared once they entered space.

3. They are exploring space without the added pressure of finding the pieces of the heart of darkness.

DeCico then said that he was not going to say which outcome he believed, but the 3rd option has the most to add to the imagination.

Also when I commented on Auman's facebook page that Turtle's (Temporal Clone version) go into space it does open the door to a spin-off series. Auman responded by liking it. So having a Spin-Off with the Turtles exploring and having adventures in space...just for the sake of exploring and having adventures in space and nothing else is not out of the realm of possibility. This way the Turtles can visit D'hoonib, encounter and fight the federation, maybe visit Stump's arena, and add further locations, ideas, and characters to the Turtle's Lore.

So O'Neil files, could make a good Miniseries. TMNT in space, could be a good Spin-Off series.

There is also the possibility of Prequel and Sequel series

A prequel series would need to get a new cast for the TMNT or in the case of Rob Paulsen and Greg Cipes just kidify their voices. We know there are child models of Mikey because of Journey to the Center of Mikey's mind. And in an upcoming episode, we do have a brief moment where we see a child version of another of the turtles.

So having a Turtle's in training series isn't impossible and it could work as a series, mini-series, or TV special.

And for a continuation series you just need to set the story at least a year or so after the main series ends, and just take "Teenager" out of the title. Instead, call it "Mutant Ninja Warrior Turtles." This could also work as a new series, mini-series, or made for TV special.

So just because this current series is coming to a close, it doesn't mean the story is dying. The stories may very well continue, but the story as we know it is over.