this command should work i think
download the new agent
extract the setup files
create a new package (zip file)
OCSAgentSetup.exe /S /UPGRADE /NOSPLASH /NO_SYSTRAY /NOW /SSL=1 /SERVER=yourserver/ocsinventory /CA=yourcert.crt
and via OCS-Inventory teldeploy use the "execute action"
It will take some time and the new version will only be reported the next time the agent contacts the server (default 24 h, but can be changed to 1h)
http://ask.ocsinventory-ng.org/6075/agent-upgrade-via-ocs-stay-notified
But in the past many persons have problems with the ocs service, because some files are in use.
For my agent upgrade i created a windows task which installs the agent at a later time, so the ocs-service doesn't need to kill itself.
The task script with the new agent was deplyoed via OCS-Inventory teledeploy
Kind regards