Please note that the OS update requires a restart of your Watchguard, so you will experience a few minutes of downtime in your services

1. Generate a backup of your Firewall device configuration, using the Watchguard System Manager application

2. Download the current OS file by visiting the Watchguard website www.watchguard.com/, navigating to Support/Software downloads/. Select your device model and download the Fireware 12.1.3 Sysa-dl file for OS updates from the Web UI. Decompress it on your PC

3. Go to System/Update the operating system, choose the option 'I have an update file' and select the file you downloaded and decompressed on your PC. Click on 'Update' and wait while it loads. Once finished, you will need to restart your Watchguard