Volume 4, 2001 +
In December of 2001, Peter Laird, now in 100% possession of the rights to the TMNT as Kevin Eastman has decided to devote 100% to his Heavy Metal productions, published the first issue of a fourth volume of the Teenage Mutant Ninja Turtles entitled "TMNT : Teenage Mutant Ninja Turtles." It's a bi-monthly return to the black & white feel not of the Image series before it, but the original Mirage Studios series... duotones intact.
Ironically, the Turtles are no longer teenagers at all, but 32 years of age. Many changes are about, the first of which seems to be the Turtles have recovered from all of the injuries suffered during their 18th and 19th years (Don's not a cyborg, Raph's eye and face is okay, and Leo's got both hands). Splinter is still alive, if now all the more elderly, and is acting as something of a father figure and mentor to Shadow.
Dramatically changing the landscape of TMNT, the alien Utroms land and conduct a conference with the United Nations... and all mutants and aliens - TMNT included - no longer need to live their lives in the shadows of sewers and mausoleums, but in the open living freely with humanity.
Friendly faces from the past return, and at #10 the unthinkable happened... Splinter, the Turtles' sensei and father figure for their entire lives, passed on.
The series is ongoing, and has even spawned a second volume of the "Tales of the Teenage Mutant Ninja Turtles," now simply titled "Tales of the TMNT." See further information about these series on the official TMNT site here.
The book is currently on "indefinite hiatus" after #28 as Laird worked on the movie. With his involvement presumably finished on the film, it remains to be seen if he'll return to it or not.