The end begins when Star Wars Rebels returns with its final episodes.
Monday, February 19 at 9pm EDT on Disney XD.
StarWars.com had the following details for the final episodes on their news article here:
Star Wars Rebels strikes back on Monday, February 19 (9:00 p.m. EDT), on Disney XD, kicking off a string of brand-new episodes, all building toward its grand series finale. The final episodes of the series will unfold over three weeks with two back-to-back episodes premiering every Monday night on Disney XD until its epic 90-minute conclusion on Monday, March 5 (8:30 p.m. EDT). The official key art for the final installments is below — a striking image of the Ghost crew facing the might of the Empire.