When does Phineas and Ferb return?

Phineas and Ferb is an American animated musical-comedy television series. It aired on Disney Channel and Disney XD for four seasons between 2007 and 2015. The series follows the adventures of stepbrothers Phineas Flynn and Ferb Fletcher, who are between eight and ten years old. The boys undertake the construction of a grand project, or embark on a spectacular adventure, to make the most of their time on vacation. The show won a Daytime Emmy Award in 2010 for Outstanding Writing in Animation, and won several Emmy Awards.
The series follows the adventures of stepbrothers Phineas Flynn and Ferb Fletcher, who are between eight and ten years old. They live in the fictional city of Danville in an unspecified tri-state area. Often these adventures involve elaborate, life-sized and ostensibly dangerous construction projects.