We're told that Sigma will announce at least one more ART series lens in 2015. It's expected we're going to see an 85mm f/1.4 ART at some point, as well as an ultra wide ART zoom.
Availability may not come until 2016, but Sigma will continue down their aggressive product development cycle.
Their most recent lens, the 24-35mm f/2 ART has been met with a mix of feelings, but all the early reviews say it is continuing the ART series level of performance.
More to come…