Soon we hope to finalize osgEarth 2.10. This is the culmination of the master branch, where the major focus has been on transitioning to a new default terrain engine ("rex") and support GL3/GLCORE profiles as robustly as possible.
Other changes include compatibility with the OSG 3.6.x release, the end of integrated Qt support in accordance with the externalization of osgQt from OSG, and removal of old, unused, and deprecated classes.
Feel free to examine the "210prep" branch on GitHub, which has updated release notes.
In the meantime if you have any final requests, comments, questions, etc. regarding this release, now if the time to speak up!