@Cyan:
Every movie since First Class exists solely to further destroy The Last Stand.
At this point they're past destroying The Last Stand and on to pretending like it never happened. Literally.
And it was so bad the other movies in the timeline had to suffer. Guilty by association.
–- Update From New Post Merge ---
Is X-Men (the first one) still canon? After all, Logan resumes at a time period when he's a teacher at the school.
http://www.hollywoodreporter.com/heat-vision/x-men-movie-canon-has-823530
It's more than likely X-Men 1 -3 are not canon anymore.