Wolverine will go back in time to stop an event that causes the Setinel project. This is as much as we know. Now some of you have said that all movies after First Class will be erased. Some of you are begging for Origins and X3 to be erased. This is my theory:
-What will be the new continuity? All the events from First Class to The Wolverine are in continuity. While not a favorable decision, it would make no sense to completely erase 5 movies (3 of them were great, 2 weren't terrible). Minor changes could be made, but the overall events should remain. This way they can continue this timeline with sequels such as the next Wolverine, First Class 2, etc. However, if they go ahead with erasing everything, maybe as Wolverine's mind travels back to it's current body, we see flashes of what's changed.
-What exactly will Logan remember? I think he will remember everything from the end of Origins up to DOFP. I think when he awakes in the current timeline, he will be the only one with knowledge of the first timeline, and no knowledge of what has happened in the new timeline.
-What are the timelines I'm talking about?
1. Begining of Origins and the WWII scene from The Wolverine(1845-1960's),First Class, the past part of DOFP(1973), end of Origins(1973-1979), X1 through The Wolverine(2000-2013), future part of DOFP (2000+?)
2. Begining of Origins and the WWII scene from The Wolverine(1845-1960's),First Class, new past part of DOFP(1973), end of Origins(1973-1979), X1 through The Wolverine(2000-2013). Since the Setinel ruled future was averted, something new takes it's place.
Just to summarize in case I lost you (hell, I lost myself proofreading the damn thing), All major events happened, the only thing that will be erased is the Setinel ruled future of DOFP, Logan will be the only one to remember said-future, and we get a surprise as to what took the place of that future. Are we good? Good.
What do guys think? I must confess, my only knowledge of time travel comes from comics, The Butterfly Effect, and the first 3 Terminator films, so please be gentle.