Sony are on record (in Japanese) saying that DSD playback functionality couldn't be added to their hi-res portable audio line via firmware. That was the Sony of September 2013. The Sony of March 2014 ain't having none of that. No no. Today they're like: "We'as jus' goofin' yo!" (Remember, Sony dig doing new things just because they're new.)
Unless the joke's on us, April will be the month of the DSD-capable Walkman. Both Sony Hi-Res Walkmans, the NW-ZX1 and F880, will get DSD-enabling firmware updates.