Andy Rose

The CMS detector and its off-detector electronics have undergone a number of changes from its original design to take on the challenges posed by the ever-increasing luminosity, to maximize the data-taking efficiency, and optimize the data quality. UK CMS, and in particular Imperial, were the key proponents of a number of changes - both incremental and radical - to the level-1 trigger in the phase-1 upgrade. I will present a recap of the proposed changes and examine what was eventually installed, and then move on to discuss the challenges faced at CMS at the HL-LHC, and the proposed upgrades to the detector and off-detector electronics needed to rise to these challenges.