The APM 2.6 board & Crius AIOP V2 have identical ATMega 2560-16 microcontroller & same MS5611 Baro chip.
The Crius board has onboard HMC5883 Mag but this can be easily disabled by cutting jumper the same as APM2.6. The only difference I can see is that APM2.6 uses MPU6000 whereas Crius uses MPU6050 for gyro/acc. The Crius AIOP V2 also has datalogging 16Mb onboard.
Has anyone tried running any of the APM versions on this latest Crius board?