We've released a new beta branch for FSX:SE that will help us gain valuable new telemetry data that will help us in the development of the new Microsoft Flight Simulator. If you are interested in assisting us with this process, please follow the link below, select the branch labeled fsx-beta – External Beta and select “yes” when asked if you allow telemetry. Remember that you are always able to opt out of the beta branch and return to the normal branch at any time.
To join the FSX beta follow these simple steps:
1. Right Click on the FSX: Steam Edition in your Steam Library.
2. Select Properties.
3. Select BETA Tab.

4. Choose fsx-beta External Beta branch. You DO NOT NEED a code.
5. Restart your Steam Client.
To reverse the changes and go to live build once again, just select branch - NONE and restart your steam client.
Included in this update are also a number of fixes, which you can find below:
CHANGELIST:
Turbine
Agent radar
Conversion
Piston
Live Weather
FSX:SE Team