You can install Administration Server version 15 on every Kaspersky Security Center Linux failover cluster node where the Administration Server with an earlier version is installed (starting from version 14). When upgrading to version 15, all data and settings from the previous version of Administration Server are preserved.
If you previously installed Kaspersky Security Center Linux on devices locally, you can also upgrade Kaspersky Security Center Linux on these devices by using the installation file or through backup.
To upgrade Kaspersky Security Center Linux on the Kaspersky Security Center Linux failover cluster nodes:
For example, you can use the following commands in the command-line terminal under an account with root privileges:
$ sudo yum install ./ksc64-<version number>-<build number>.x86_64.rpm
$ sudo apt-get install ./ksc64_<version number>-<build number>_amd64.deb
After the command has been successfully executed, the /opt/kaspersky/ksc64/lib/bin/setup/postinstall.pl script is created. The message about that is displayed in the terminal.
Installation of the application on your device will continue after you have entered 'Y' twice.
The picture below shows the last two steps.

Accepting the terms of the EULA and the Privacy Policy, and selecting the installation mode in the command-line terminal
Next, the script configures and finishes upgrading the Administration Server. During the upgrade, you cannot change the Administration Server settings adjusted before the upgrade.
At step 6, enter '3' to select the node.
Note that you can start the cluster on any node. If you start the cluster on the passive node, it becomes the active node.
As a result, you installed the Administration Server of the latest version on the Kaspersky Security Center Linux failover cluster nodes.