The Rails team has recently announced the timeline. Beta rounds are beginning in January and February; release candidates are March and April; and a hopeful final release date of April 30th has been set! Now obviously this can, and may, change. But, it’s a pretty solid bet at this point that we’re going to see a 6.0 release 2019Q2.
Rails 6.0 does require Ruby 2.5+. I know most hosts are still running 2.2/2.3. So if you’re stuck using a slow-to-upgrade shared host, you may find yourself waiting before you can deploy any Rails 6.0 applications.
There are a number of changes coming with Rails 6.0 that I’m particularly looking forward to. Particularly in ActiveRecord. I think I’ll make a post or two following this, over the next couple of days, digging deeper into these features and how they can be used.