France's Canal J just aired the final two episodes of Power Rangers Megaforce and RangerCrew's YellowAccel posted the SPOILERS about it.
The Rangers defeated the Warstar, but the fight is not over because Metal Alice turned Vrak into a cyborg without his memories. To make matters worse, the Messenger arrives and tells Metal Alice that the everything is ready for the invasion. Vrak later recovered his memories thanks to Metal Alice and fights the Rangers. Meanwhile, the Messenger calls the Armada and we see a shot of the Zangyack ship and hear Prince Vekar (?)'s voice.
In the final episode, after the fight against Vrak, the Morphers are burnt. The Messenger arrives and tells them that Vrak is the Prince's brother. He attacks the Rangers and they revert back to normal. Even with their burnt Morphers, our heroes want to continue the fight and fights the Messenger unmorphed.
Robo Knight stops them and he transferred his energy in his Morpher to send a powerful attack. He absorb the Messenger's attack and use it to repair the Morphers. He then gives his Blaster to Troy and can't fight anymore. With their powers back, they defeat the Messenger but before he dies, he revealed that he is the first of a long list of invaders that will attack Earth.
Vrak arrives and the Rangers tried to finish him but Metal Alice protects him. The Rangers fight her and eventually, defeat her. Vrak kills her because she failed. The Messenger's head is on the ground and it seems he can talk. He tell to Vrak to ran away, because the armada is mostly here and they will not recognize him now that he is a cyborg.
The Rangers demorph and started their search for Robo Knight but he is not here anymore. Gosei calls them and he is panicking and tells the Rangers to morph quickly. The Rangers morph and the Armada arrives to attack the Earth. The Rangers run in a forest. Troy said that he has to find Robo Knight and runs.
And that's it, that's how Power Rangers Megaforce ended, it ended with a cliffhanger.