I have a 7 or 8 year old Crestron system/project that uses RTI T2-C remotes with Crestron gateways. One of them is defective and can't be repaired. What model RTI T2-C can i replace it with?

FYI: The T2-C+ (what i have been replacing T2-C remotes with) is no longer available from RTI so that is not an option.

ID (Integration Designer software) wont let me convert to a T2-Cs...does that mean it won't work with the same type of gateway? Or does it just mean i have to manually convert the file so that it works with a T2-Cs?