According to PortableApps.com Updater - Your Apps Are Up To Date:
"When a new security fix for your browser is released or a new feature in your favorite game is available, the PortableApps.com Updater will automatically let you know."
However, Options=>Updater only has Check for updates for On platform startup, which indicates there are hardly any updates since the platform is supposed to remain open all the time albeit the occasional restart.
Can you indicate which is it?