The Wrap has updated its initial report (which has now been backed by all the major Hollywood trades) to include more details about Warner Bros.' plans to bring Michael Keaton's Batman back to the big screen. The site explains that the general plot of The Flash will revolve around the Multiverse, with "Robert Pattinson's Bruce Wayne [still] viewed as the future of the franchise."
In other words, it's sounding increasingly likely that The Batman will be a standalone franchise not all that different to Joker. Regardless, The Flash will reportedly see the Scarlet Speedster travel back in time to prevent the death of his mother, an act which leads to the creation of another universe.
If that sounds familiar, it's because that was essentially the plot of the Flashpoint comic book series.
They go on to explain that this new reality is protected by Keaton's version of Batman, and both Batman Forever and Batman & Robin will be forgotten about, with The Flash revealing what this Dark Knight has been up to in the thirty years since we last saw him face The Penguin in Batman Returns.
It seems likely that this newly created world will be here to stay, especially as it's being widely reported that Keaton's Batman will stick around, acting as a mentor to a number of heroes (including Batgirl).
This would also explain the disappearance of Ben Affleck's Dark Knight, but will leave the main DCEU with a Batman who has probably retired. It's an interesting, and exciting, move, that's for sure...