The Large Hadron–Electron Collider (LHeC) is designed to move the field of deep inelastic scattering (DIS) to the energy and intensity frontier of particle physics. Exploiting energy- recovery technology, it collides a novel, intense electron beam with a proton or ion beam from the High-Luminosity Large Hadron Collider (HL-LHC). The accelerator and interaction regions are designed for concurrent electron–proton and proton–proton operations. This paper represents the concepts of an updated LHeC design study and discusses the design challenges of the project.