Functionally, whats the difference between APM 1.4 and 2.x?

I have an old (Brand New) APM 1.4 that I’m thinking of putting in an EasyStar. I use an APM 2.5 on my Hexcopter.
Functionally, what is the difference? I realize there is no onboard magnetometer and the GPS (Mediatek V12) is very oldschool. Other than that, is there any reason to not use this? I was thinking of adding a magnetometer to it.

Any input on this? I’d hate to just dump it because it’s old.

Thanks…Don.

Hello?? Anyone home?

Hi Don,

Here is some information:
copter.ardupilot.com/wiki/common … _and_APM_2