Looks like the Teenage Mutant Ninja Turtles we all know and love are growing up. The team of crime-fighting turtles, who will not be mutants in Michael Bay’s upcoming film, will reportedly not be teenagers either.

According to Bleeding Cool, the most recent update to the franchise is going by the working title Ninja Turtles.

The live action film's title has been verified, even though the age of the turtles has not, leading the rest of us to believe that Bay is indeed tossing the formerly mutant turtles as "teenagers" idea.

"It seems to be driven by marketing. Think of John Carter and how Disney wouldn’t allow for a title with either 'Princess' or 'Mars,'" an unnamed source told Bleeding Cool. And we all know how well that worked out for Disney.

The recent title shortening is the most recently announced change from the original concept, which spawned an animated TV series, several films and a line of merchandise. Bay stopped by Nickelodeon Upfront earlier this month and revealed that he would be making a significant change to the turtles’ origins -- instead of mutants, they would be aliens.

The news was received with much outrage by fans of the original series, along with Turtle alums, including Robbie Rist, who voiced Michelangelo in the 1990 film. Bay responded on his website, telling fans to "take a breath, and chill," explaining that the film's team is "building a richer world."

But that didn't stop some fans from taking to Twitter and voicing their concerns with Bay's creative liberties.

Check out some of the Twitter reactions in the gallery below.

The newest live action "Teenage Mutant Minja Turtles" movie is tentatively set for a December 2013 release. Watch Bay talk about the film below.