We provide detailed instructions for upgrading to the latest version of Access Server here:
Generally, the process of upgrading involves using the package manager in the operating system to release any present hold on the package ‘openvpn-as’, instructing it to get the latest version, and installing it. Your settings and licenses remain intact during this process. This process holds true for Access Server version 2.7.5 and above.
For Access Servers running versions older than 2.7.5, the software repository was not yet the default installation method. Since this was a fairly long time ago, you should first check your operating system version to see if it’s still supported before trying to upgrade. You can find our supported operating systems here: OpenVPN Access Server system requirements