As a general rule, prior to upgrade you should back up your DualShield server files and database. If your DualShield server machine is a virtual machine then you can simply take a snapshot. If your DualShield server is using an external SQL database server then you must also back up the database separately. 

You should always upgrade the DualShield server first, then the DualShield agents. If your DualShield system consist of DualShield backend servers and front end servers, then you should upgrade the backend servers first.

Single Server System

The article below contains general guideline for upgrading DualShield Server: 

How to upgrade a DualShield server to a newer version.

Multiple Server System

If your DualShield system consists of multiple DualShield servers in a high availability cluster, then you must follow the process below to upgrade the system.

Typically, you would have two DualShield servers set up as a MySQL Dual-Master or MS-SQL Merge-Replication cluster. For the description purpose, let us call them Master/Publisher and Slave/Subscriber.

Step 1: Check all SQL servers in the cluster, make sure they are in sync. See: 

Step 2: Upgrade the Master/Publisher server first (VERY IMPORTANT for MS-SQL Merge Replication. Do NOT upgrade the Subscriber/Slave server first)

Step 3: Wait for the Master/Publisher server to complete the upgrade process. See: 

How to check if a DualShield server is fully started.

Step 4: Check both the Master/Publisher and Slave/Subscriber SQL server in the cluster again, make sure that they are in sync.

Step 5: Upgrade the Slave/Subscriber server

Framework Upgrade

DualShield server is a JAVA application. It runs on a framework that consists of 3 components, namely Tomcat, Java Runtime Environment (JRE) and MySQL database engine. From time to time, those framework components might need to be upgraded.

DualShield install its own copy of Tomcat, JRE and MySQL. It does not use or share other instances of Tomcat, JRE or MySQL that might have been also installed on the same machine by other applications. Therefore, upgrading other instances of Tomcat, Java or MySQL has no effect on DualShield. To upgrade the framework components used by DualShield you must use the framework upgrade tool supplied by Deepnet Security in the DualShield platform. You should not attempt to upgrade the framework components in the DualShield platform using other third party tools.