My understanding of the Disney canon is that everything was purged. This would include all the Old Republic games and comics books associated with them that mentioned the Mandalorian War.
In the episode of Star Wars: Rebels "Trials of the Darksaber", however, Kanan gets angry at Sabine for attacking him with Mandalorian tricks and said:
History lesson: the Jedi won the war with Mandalore.
Is Kanan referring to the Mandalorian War here, and are there any other sources more obviously confirming that the Mandalorian War happened in the new canon?