The invention relates to a plate package and a plate heat exchanger. The plate package includes plate modules with two heat exchanger plates (3), which extend at at least an intermediate plane, and upper and lower planes. The heat exchanger plates are permanently connected to each other and form an inner first space therebetween. The plate modules are stacked to each other and form a second space therebetween. Each heat exchanger plate includes two portholes (13) which permit communication with the first space. Each porthole is defined by a port edge (31) and surrounded by a ring groove (32) for a gasket member. The ring groove is formed by a bottom (33) at the level of the intermediate plane, an inner lateral limitation (34) and an outer lateral limitation (35). The outer lateral limitation forms a surface extending without any interruptions. The inner lateral limitation includes interruptions.