The invention refers to a plate package and a plate heat exchanger. The plate package includes plate modules with two heat exchanger plates (3), which extend at least an intermediate plane, an upper plane and a lower plane. 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 at a distance from the port edge. The ring groove is formed by a bottom (33) at the level of the intermediate plane, an inner lateral limitation (34) extending upwardly from the bottom towards the port edge, and an outer lateral limitation (35) extending upwardly from the bottom away from the port edge. The outer lateral limitation forms a surface extending without any interruptions continuously around the bottom whereas the inner lateral limitation has a discontinuous extension around the bottom and includes interruptions along this extension. (FIG.6)