Overview

When trying to upgrade the OS of the Kerio Connect Virtual Appliance, the specific instructions should be followed. Kerio Virtual Appliance is based on Debian 8 installation. The recommended procedure consists of the upgrade from Debian 8 to Debian 9, and then to Debian 10.

Prerequisites

Upgrade from Debian 8 to Debian 9 as per Upgrading Upgrading Kerio Connect on VMware guide (step 6)

Note: the full procedure about upgrading is available in Upgrades from Debian 9 guide.

Solution

1. Create a Full Backup of the Kerio Connect Data.
2. Open Kerio Connect Virtual Appliance (VA).
3. Access the VA via SSH. 
4. Update the source.list file before performing the update: Run nano /etc/apt/sources.list

   deb http://ftp.us.debian.org/debian/ buster main
   deb-src http://ftp.us.debian.org/debian/ buster main
   
   deb http://security.debian.org/ buster/updates main
   deb-src http://security.debian.org/ buster/updates main
   
   # stretch-updates, previously known as 'volatile'
   deb http://ftp.us.debian.org/debian/ buster-updates main
   deb-src http://ftp.us.debian.org/debian/ buster-updates main

   

5. Run apt update
6. Runapt-get upgrade
   
7. Run apt full-upgrade​​
8. Restart Kerio Connect.
   

Confirmation

To verify the OS version, run lsb_release -a​ command and open the Kerio Connect Administration dashboard interface.