A panel sector, for a disc filter for separation of liquids from a suspension, includes front and back filter panel assemblies, a sector assembly for mounting the front and back filter panel assemblies, and a top cap for retaining the filter panel assemblies within the sector assembly. A headbox feeds the mixture into a panel forming area over the upper surface of a continuous forming fabric to form a panel mat. First, the presence system accepts batches of publication updates in a single presence update request.