ThoughtSpot is installed or updated from a release tarball which contains the ThoughtSpot application (binaries and configuration), third-party software, and Operating System image. Third party softwares are licensed software components necessary for operation of the ThoughtSpot application. These include Java, Boost C++ libraries, Google protocol buffers, and so on.
ThoughtSpot patches the Operating System at the time of upgrades. The exact same process used during installation is also applied during upgrades. The previous OS image on a node gets replaced by the new image carried in the release tarball.