Two bits [phoronix.com] of news [phoronix.com] from WineConf 2015 via Phoronix. They're both switching to yearly releases and making wine-staging an formal part of the project.
Right now the Wine stable releases are feature-driven rather than committing to shipping on time-based schedules. For example, it was one year from Wine 1.4 to Wine 1.6 while going from Wine 1.2 to Wine 1.4 it was two years. In going from Wine 1.6 to the yet-to-be-released Wine 1.8, it's now over two years. As written about previously, Wine 1.7 Series Turn Two Years Old, No Sign Of Wine 1.8 [phoronix.com].
Moving forward, Wine developers have agreed to just do a new release every year around this time -- fall/autumn -- regardless of new features. The bi-weekly Wine development releases will continue.
For many months now Wine-Staging has been around and following the bi-weekly Wine development releases with that work plus all sorts of experimental/testing patches added on top, such as the Command-Stream Multi-Threading work. Wine-Staging has a decent following since generally they tend to carry a lot of interesting but experimental features prior to their formal introduction in the Wine code-base.
At WineConf 2015, it was decided that Wine-Staging will now be an official part of WineHQ. The Wine-Staging project will now retire their current bug-tracker in favor of the upstream Wine bug tracker, Wine-Staging will be integrated into the regular development process, and other changes will come.