The CMS Outer HCAL SiPM Upgrade

The CMS Outer Hadron Calorimeter (HO) is the first large scale hadron collider detector to use SiPMs. By late January 2014 the installation of 1656 of 2376 channels was completed. The HO readout system provides for active temperature stabilisation of the SiPMs to less than 0.1$^\circ$C using Peltier coolers, temperature measurement, and software feedback. Each channel has independently controlled bias voltage with a resolution of 25mV. Each SiPM is read out by 40MHz QIE ADCs. We report on the system design, schedule and progress. The next phase for the detector is commissioning during 2014 before the 2015 LHC run. We report on the status of commissioning and plans for operation. We discuss the calibration strategy with local cosmic ray runs using the HO's self trigger ability.