Upgrade of the Drift Tube system in CMS experiment and the associated activities.

	Drift Tube (DT) chambers make up the muon detection system in the central region of the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). An upgrade of the readout and trigger electronics of the DT system is planned considering the significant increase in the event rates and integrated radiation doses anticipated in the future high-luminosity operation of the LHC, termed as HLLHC and expected to start in late 2020s. During the second LHC long shutdown period spanning 2019-2021, prototypes of the aforementioned electronics were installed on a subset of the DT chambers in the so-called slice-test setup for testing, and to serve as a demonstrator for the planned upgrade. The details of the CMS-DT system, its upgrade and the DT slice-test will be discussed in this presentation, with a special focus on the calibration of the DT system.