That's a shame, do we know why? is it just not finished being implemented? I found a page[0] that said at some point they had stalled on refactoring something.
That's a shame and the first I've heard of the delay. For me and the software that I write, this is a must have feature and I was very much looking forward to its release.
[0] https://ghc.haskell.org/trac/ghc/wiki/Records/OverloadedReco...