Level-1 Calorimeter Trigger: From Virtex-7 to UltraScale+

With the restart of the LHC in 2021 the ATLAS experiment has to cope with high-luminosity beams. Therefore, a new Level-1 Calorimeter Trigger system will be introduced exploiting a finer calorimeter readout granularity. The new system consists of three Feature EXtractors (FEXs) - electron FEX (eFEX), jet FEX (jFEX) and global FEX (gFEX) - that use FPGAs to reconstruct different physics objects used for the trigger selection and that gather data from the calorimeters through optical fibres. The Trigger Objects (TOBs) produced by the algorithms running on the FEXs are optically sent to the Level-1 Topological Processor (L1Topo), where interesting physics events are selected by e.g. applying kinematic and angular requirements. This contribution will focus on the new jFEX system and on the upgrade of the L1Topo giving an overview of the hardware as well as the algorithmic firmware.