OpenVPN Client - check the version and update.

Check the botton of the Client window to see the version number:

If you are running client version 3.3.4 or higher, then getting the update is easy. Click the Settings link:

Scroll down the list until you see Software update. Click on Check Now and the click on the notificaiton that appears on the bottom right corner of your screen for Windows or the upper right for macOSWhen you click this notification, your default browser will download the latest update. Just go to that download and run the installer. And now you're all set with the latest client version.

However, if your OpenVPN Client version is older that 3.3.4, it's possible you will not see the "Check now" option for updates. In that case, visit this link and download the latest OpenVPN Client for Windows or macOS. 

This will give you the latest client verison.