Improved alt hold: Look for about twice the accuracy for altitude hold than the previous 2.0.40 preview. It's really good and the motors don't pulse as hard as they did before.
Loiter looks great and has the wind compensation turned on now by default. It wasn't enabled before.
RTL is running very smooth. Circle mode needs some work. Installing this will cause you to go through an initial setup process using the CLI. Be sure to setup your radio, level, enable the compass, set declination and enable sonar, etc.
Feedback is appreciated.
Note: This version is no longer compatible with the Mission Planner. Some internals have changed. I'll work with Michael Oborne to get it connected and updatable through the Planner.