While the developers are already working on interesting features and new stuff in the so-called goat-invasion branch they try to push out GIMP 2.8 as soon as possible. The first release candidate (RC) has now been released to the public!
You might ask why they still do a RC because 2.7.5 worked pretty well already. There have been some discrepancies withs GIMP graph-based graphics library GEGL which is no longer fully backwards compatible. Therefore the developers had to implement their own Contrast & Brightness operation.