Does the Icinga2 master push the software update request to the clients? Do the clients call out to icinga hosted servers for updates? How does it go about getting updates or do we have to build that upgrade process. Such as pushing out the msi packages to each server being monitored?
updates must be done manually, but you can use some automation deployment software such as Puppet, Ansible, Chef, etc. which are updating your endpoints.
With the icinga command you can also check the current installed version.