The product upgrade channel is used for updating the appliance OS along with the Filr patches. This is applicable to All-in-One deployments and large deployments.
NOTE:Filr 4.3.x is available through the product upgrade only. After updating to latest Filr 4.2.3 patches and the 'Enable Update to Filr 4.3.x' patch, you can update to Filr 4.3.x through the product upgrade channel.