This is Service Pack 1 for the Super 80 Professional. It contains a number of fixes and updates to the gauge file, aircraft model and more.
Note that the product download from the Flight1 website already includes SP1. The boxed edition also includes SP1. This update is for those who purchased/downloaded the Super 80 Pro before the release of SP1.
WARNING: Service Pack 1 has been superseded by Service Pack 2. You do not need to install SP1 before installing SP2. Download SP2 here.