The "older" versions like the FD-iA6 and 6b have mixing, the "newer" versions do not.
https://img.banggood.com/thumb/water.../SKU096119.jpg
This one does have mixing enabled stock from the box.
https://img.banggood.com/images/uplo...KU073409.1.jpg
This one does too.
https://img.banggood.com/thumb/water...c4fb449d97.jpg
This one does not.