Zipcode is a message-passing and process-management system that was designed for multicomputers and homogeneous networks of computers in order to support libraries and large-scale multicomputer software. The system has evolved significantly over the last five years, based on our experiences and identified needs. Features of Zipcode that were originally unique to it, were its simultaneous support of static process groups, communication contexts, and virtual topologies, forming the "mailer" data structure. Point-to-point and collective operations reference the underlying group, and use contexts to avoid mixing up messages. Recently, we have added "gather-send" and "receive-scatter" semantics, based on persistent Zipcode "invoices," both as a means to simplify message passing, and as a means to reveal more potential runtime optimizations. Key features in Zipcode appear in the forthcoming MPI standard. Keywords: Static Process Groups, Contexts, Virtual Topologies, Point-to-Point Communica...