Two permits
were issued on March 20 for 1600 Market. One is to demolish the existing building, and the other is to erect a new 24-unit apartment building. Of course, just having the permits doesn't mean construction is imminent, but at least there appears to be some life for this site.
According to
this PDF, the plan is to construct 24 BMR units with 3770 sq. feet of ground floor retail:
Here's a story from several years ago with an old rendering (for a taller building).