Asked this in Yamaha forum with no response..guess here is where the action is..

After loading custom registration (.RGT) and sound info from a Tyros 2 onto USB stick, will they load into newer Tyros 4 or 5, or psr 970/975? I imagine adjustments would have to be made. I remember reading some things from T2 and earlier are not compatible due to changes in o.s. from T3 on?? It impacts choice of next keyboard if I have to start from scratch.