We report status of the CMS full simulation for run-2. Initially, Geant4 10.0p02 was used in sequential mode, about 16 billion events were produced for analysis of 2015-2016 data. In 2017, the CMS detector was updated: new tracking pixel detector is installed, hadronic calorimeter electronics is modified, and extra muon detectors are added. Corresponding modifications were introduced in the full simulation and Geant4 10.2p02 was adopted for 2017 simulation production, which includes improved Geant4 for the multi-threaded mode, which becomes the default for 2017.
For the 2018 Monte Carlo productions, the full simulation is updated. The new Geant4 version 10.4 will be used, it was adopted for the production after detailed validations versus test-beam and collision data. Results of validations will be described in details. Several aspects of the migration to Geant4 10.4 and modifications of CMSSW simulation software will be also discussed.