Hi,
Thank you for posting in Symantec community.
Q. is his old version fully working with all the funcionalities activated or some of the funcionalities will not work until the reboot? (Of course without forcing the reboot of the machine from SEPM, because I want to wait the user to reboot autonomously).
--> Old version functionalities will not be impacted. SEP 12.1 employs a side-by-side, replace on reboot installation strategy. Side-by-side means that new files are written to a new folder, referred to as a silo, isolated from the existing operational folder. Because the two versions are separated from each other, during a migration the older software is left running unchanged until the next reboot.
The primary benefit of side-by-side installation and replace on reboot is that the system continues to be protected by the existing software until the new version is in operation after the reboot.