Legacy flowmeters have their byteorder set at compile time. This means that to change it you will need to get a custom firmware. This situation is not ideal, and should be avoided where possible ( for insctance if the bms has an option for byteorder). It means that if you have a custom firmware, and you later want to update the firmware, you should request also a custom version of the new version.

about byteorder

digital numbers are constructed out bytes. it is not always clear which byte goes first: the most, or the least significant byte. It is similar to the difference in date-format: mm-dd-yy or dd-mm-yy. If you don't know which one is used, you will get meaningless data. This is why a lot of modbus devices have a test-register, which will for instance always yields the value 1234. If you are disagreeing on byte-order, you will get a 3412 value out of this. Unfortunately this register is not (at the moment of writing) in our flowmeters.