the fecu KDU13013/4 isn´t any longer available so you have to use an integrated license
and therefore you need min CSW R14 and a flashcard in the system (MFU, VMU-HD, CPU-D5, IPU, SIPU).
Why do you want to upgrade the system to R13, it is phased out since round about 10 years?!
I would update the system to R18 and buy a integrated license.
What do you want to do with the BTU-D?
A upgrade instruction can be found in the BMS help.