As mentioned on the 3.5.2 release discussion we have decided to do a 3.5.3 release to fix a couple of important bugs found by users in 3.5.2. The main motivation for the release is a problem with flying without a compass enabled. If you fly 3.5.2 with MAG_ENABLE=0 or no compass attached then there is a risk that the EKF2 attitude estimator may become unstable before takeoff. This can cause the aircraft to crash.
The other changes in the 3.5.2 release are more minor:
- fixed loiter radius for counter-clockwise loiter
- fixed the loiter radius when doing a RTL at the end of a mission
- provide reasons to the GCS when a uBlox GPS fails to properly configure
- support a wider variety of NMEA GPS receivers
- use EKF1 by default if no compass is enabled