Yes, I'm working on a second edition now. All code will be brought up to current releases (the 2018 Edition being part of that), including the crates and modules chapter, and we'll have a new chapter on async programming. The chapter on references does need to be updated to cover non-lexical lifetimes, but the intuitions are all still the same.
I think almost all of the book should still be helpful. Our focus has always been on explanation and getting readers to the point where they can learn the rest on their own, not exhaustiveness (that's for docs) or specification-level precision (that's for, uh, specifications), and that should age well.
O'Reilly is very, very keen to have the second edition out in 2020, as soon as possible; it's sold well. But I'm incredibly slow, so I think the first half of the year is unlikely.
(If you've ever thought about pitching a Rust book to O'Reilly, now is the time to do it. They're really impressed with Rust's momentum, and looking for authors. Drop me a note at jimb@mozilla.com.)