(Medium credibility rumor):
Image on top shows the current Sigma ART E-mount lens lineup.
There is a rumor coming form the Sigma front. According to one source:
Sigma is readying a new 24mm f/2.8 DN Art lens for APS-C E-Mount. Expect higher sharpness when compared to the 30mm, about the same level of sharpness as with the 60mm. Autofocus is speedier too compared to the 30mm. Announcement will come very soon within September.
We also heard from another source the lens will be available for Micro Four Thirds too!