Just bought a twinsync from TroyBuilt. Can I take the chip from it and put in in my older, 2.3.1 unit? If so then could I send the older chip to be updated?

BTW what are the changes from 2.3.1 to 2.4. I.E. is it worth doing. My inclination is to do so.

The unit comes with mode 4 set for fast Gas engines. I am using two OS 81 four stroke engines. Since you have a setting for glow I changed to the recommended setting for glow. A second unit will be used with two OS 55 2S and I expect to go to the recommended for fast glow. The third unit will be controlling two RCVS 26CC gas engines so I expect the factory default (fast gas engines) is correct. Since you state I should check with tech support about this, I am doing so now.