That's interesting, he's using the Ninja Tribunal symbol. I wonder if that's intentional or if the artist just flipped the Foot Clan symbol upside down without realising it had been done before?

https://www.cbr.com/tmnt-shredder-exclusive-first-look/
Per the official solicitation synopsis for Teenage Mutant Ninja Turtles: Shredder #1, "As a dark new power rises from the shadows of New York, so does a much darker power return to the city’s streets…for revenge. One of the most terrifying villains in the history of comics is back—and more deadly than ever!"

The solicitation continues, "Returned forever changed by a maddening ordeal beyond imagining, the Shredder is a man out of time, betrayed by all around him, without the Foot Clan, and quite possibly insane. When one of his former Foot prodigies forms their own rival clan with infernal designs on New York, a recovering Shredder must quest deep into the criminal underworld, where enemies both old and new will discover what defiance will bring them at the end of the Shredder’s blades."

In the primary IDW Publishing Teenage Mutant Ninja Turtles timeline, Oroku Saki has spent recent years playing the role of guardian angel and mentor to the Turtles, although it seems like all that might be changing with the impending release of Teenage Mutant Ninja Turtles: Shredder.