  Research software plays a crucial role in advancing scientific knowledge, but
ensuring its sustainability, maintainability, and long-term viability is an
ongoing challenge. The Sustainable Research Software Institute (SRSI) Model has
been designed to address the concerns, and presents a comprehensive framework
designed to promote sustainable practices in the research software community.
However the SRSI Model does not address the transitional requirements for the
Exascale Computing Project (ECP) Software Technology (ECP-ST) focus area
specifically. This white paper provides an overview and detailed description of
how ECP-ST will transition into the SRSI in a compressed time frame that a)
meets the needs of the ECP end-of-technical-activities deadline; and b) ensures
the continuity of the sustainability efforts that are already underway.
