In conjunction with the CP+ show in Japan, Sigma announced four new lenses, though pricing and availability details were not disclosed.
The lenses are the 14mm f/1.8 Art, the 135mm f/1.8 Art, the 24-70mm f/2.8 Art, and the 100-400mm f/5-6.3 Contemporary. All these lenses are available in the Canon EF, Nikon F, and Sigma SA mount. The 14mm f/1.8 is clearly something new with no real competitor, the 135mm a close second. The other two lenses appear to be rethinks of earlier Sigma lenses.
At this point there's not a lot more than the press release, product specifications, and press images of the lenses available. I have updated the lens database pages to include all the new lenses, and as the final details trickle in I'll update those.