CMS Forward Calorimetry R\&D for Phase II Upgrade

Forward calorimeters in CMS will need to be upgraded for the High Luminosity LHC (HL-LHC) operations, which is planned to be started in 2025. The major challenge is to preserve/improve the high performance of the current forward detectors while designing the detectors considerably radiation hard. This report will concentrate on the need for the upgrade, major challenges and various proposed R\&D concepts suitable for the Phase II upgrade framework. Various designs will be discussed with recent information about the beam tests and laboratory measurements.