Bergdorf Goodman doesn’t list dimensions for this bag, but on-model comparisons make it look notably larger than the popular small size, and YSL appears to have removed the medium, the bag’s largest version, from its website.
Just from eyeballing it, this bag looks similar to the medium, but with a shoulder strap and a softer structure that will give it some nice slouch when carried by that strap. The medium always looked a little too big to be an arm-only bag and its size already tended a bit more toward slouchiness than the smaller versions, so this seems like a logical next step for the larger end of the SDJ line.
The bag appears to be made of double-sided leather instead of lined in a different material, which should help lighten up such a large bag. the Supple SDJ maintains the zippered middle compartment that most sizes of the bag have, but it appears to lack other interior compartments. On the outside, the biggest changes are the exposed pegs that hold the gusset belts in place at the front top corners.