Backwards compatible means that new products are compatible, i.e. work, with older ones. So Di2 12 speed is not generally backwards compatible.
The question you want answered is, are all 12 speed Di2 products interchangeable, i.e. will they work with components from different groupsets that are also 12 speed? The answer to that, as I understand it, is yes.
Backwards compatible means that new products are compatible, i.e. work, with older ones. So Di2 12 speed is not generally backwards compatible.
The question you want answered is, are all 12 speed Di2 products interchangeable, i.e. will they work with components from different groupsets that are also 12 speed? The answer to that, as I understand it, is yes.