In view of the challenging data taking of CMS in HL-LHC Collisions, an extensive upgrade is
underway for the CMS Muon System to ensure its optimal performance in muon triggering and
reconstruction. The key role of RPCs as dedicated muon detectors will provide relevant timing
information, profiting of their time resolution, to secure sub-bunch crossing event timestamp. To
meet the requirements of LHC Phase-2, the RPC system will be expanded up to 2.4 in pseudo-
rapidity. The forward Muon system’s upcoming RE3/1 and RE4/1 stations will feature improved
RPCs (iRPC). Distinguished by a unique design and geometry, including a 2D strip readout, these
iRPCs represent a significant advancement over the current RPC system. The enhancements
include the use of thinner electrodes, a narrower 1.4 mm gas gap, and improved FEB allowing
a 30 fC threshold. At the end of 2023, two iRPC chambers were installed in the CMS detector.
Present paper provides a full summary of the iRPC project

