LAUSR

These proceedings report the current plans to upgrade the ATLAS detector at CERN for the High Luminosity LHC (HL-LHC). The HL-LHC is expected to start operations in the middle of 2026, aiming to reach an ultimate peak instantaneous luminosity of $$7.5\times 10^{34}~\hbox {cm}^{-2}~\hbox {s}^{-1}$$7.5×1034cm-2s-1, corresponding to approximately 200 inelastic proton–proton collisions per bunch crossing, and to deliver over a period of twelve years more than ten times the integrated luminosity of the large hadron collider (LHC) Runs 1–3 combined (up to $$4000\,\text{ fb }^{-1}$$4000fb-1). This is a huge challenge to all sub-systems of the detector which will need extensive upgrades to allow the experiment to pursue a rich and interesting physics programme in the future.