When Matt Reeves came on board to helm The Batman, he ditched Ben Affleck and Geoff Johns' script and decided to start from scratch. Understandably, it's taken him quite some time to put a new draft together (these things don't just write themselves overnight) but it sounds like some real progress has finally been made as a new report claims that a first draft has been turned into Warner Bros.
Now, the studio can work with Reeves to establish what direction the movie will be taken in and that should then lead to pre-production beginning in earnest, with concept art and the like put together before shooting begins at some point in 2019. This may also mean that we'll find out who will be replacing Ben Affleck's version of the Caped Crusader as it's said that Reeves wants someone new.
It is, of course, possible that Affleck will return but it seems highly unlikely given everything that's happened and it's been reported a number of times that the director is hoping to make use of a younger version of the hero. Something else we don't know is if this will be a standalone adventure or set in the DCEU with links to the Justice League and actors like Jeremy Iron and J.K. Simmons.