Lockheed Martin announced the new version 3 of PREPAR3D. I will need some time to check if SIMstarter is or it will become compatible with P3Dv3. So far the current versions of SIMstarter are not supported!
[Update 02.10.2015]
A new BETA revision which contains compatability with P3Dv3 is out to the BETA testers… The new v2.7 will be delayed and will be v3 ready!