To upgrade the PCNS Virtual Appliance, you do not need to deploy a new copy of the Appliance and run the Setup Wizard.
You can now upgrade the version of PCNS running on the Virtual Appliance using the ESXi installation files: This method will retain your existing configuration settings.
Download the latest version of the PCNS for VMware ESXi installation file to your PC. For example, the ESXi installation file for v4.2 is available from the link below:

https://www.apc.com/ie/en/tools/download/software_comp.cfm?sw_sku=SFPCNS42-V

Login to the Virtual Appliance console as the root user using PuTTY or another SSH Client. If you cannot login using SSH, please review FA222181.
In the console, create a temporary directory, for example /opt/temp

sudo mkdir /opt/temp
change directory to /opt the command is cd /opt  
Verify the permission on the temp directory. the command is ls -la 
 The temp directory should have the permissions of rwxr-xr-x 

Copy the previously downloaded installation file from your local PC to the temporary directory using WinSCP or other FTP/SCP program being sure the user is root.
In the console, change to the temporary directory and uncompress the installation file


from /opt/temp run these commands
gunzip pcns420ESXi.tar.gz
tar -xvf pcns420ESXi.tar

This will create a new directory called ESXi, so change to this directory

cd ESXi

Run the installation script and follow the instructions

sudo ./install_en.sh