User blog comment:Crimson and Darkness/DxD Updates 2~/@comment-25072311-20170823085817/@comment-1359322-20170901042818

Technically EX didn't made BorN non-canon. There are other timelines besides BorN as well as seen in the quote below

"Kurenai then spoke while scowling.

"The time period we are from——the world of the future, is a parallel world, or at least that's according to someone who has the faculty of being able to observe the timeline. Based on what that person said, this timeline is undisturbed, but that the history of other timelines is already different with each step you take forward."

"There's a certain timeline in which the Seirei of the Chichigami did not appear. Since there was no contact with the Chichigami, there apparently wasn't any inference made about the existence of a parallel dimension.""

If anything it means BorN is a canon event taking place in an alternate timeline. This may be used to explain some deviating events in the anime like how Akeno, Irina, Tsubaki were involved in the V4 event during New.