RE: Finally!! 8U/9C synthetic module due out..
As far as intercompatibility is concerned, all Futaba transmitters on FM-PPM are compatible with all Futaba FM-PPM receivers. All Futaba transmitters operating on PCM1024 are compatible with all Futaba receivers operating on PCM1024. If a non-Futaba receiver has problems working with a Futaba transmitter, it's a problem in the receiver, not a Futaba "problem".
We'd not know of any modification or "upgrade" to make a Futaba tranmitter compatible with a non-Futaba receiver. If a transmitter was sent in to us where the user complained that it didn't work with their non-Futaba receiver, we'd make sure the transmitter operated correctly per Futaba's specs. If the customer's non-Futaba receiver still didn't work with the Futaba transmitter, it's not Futaba's problem.
(edit for typos)