[…] ATLAS produced a Conceptual Design Report (CDR) for HL-LHC Computing during the spring of 2020 for an initial review by the LHCC. The CDR laid out the issues discussed above, and the general approaches that will be taken to address them. This new document serves as a software-focused update to the first CDR, providing more concrete information on development work that will be undertaken in the coming years, listing specific milestones and target dates. Additionally, the document describes how ATLAS collaborates with external activities and projects, and how such collaboration will impact the overall development for HL-LHC.