The latest Official Release of HDF is 4.2.9
HDF (also known as HDF4) is a library and multi-object file format for storing and managing data between machines. There are two versions of HDF: HDF4 and HDF5. HDF4 is the first HDF format. Although HDF4 is still funded, new users that are not constrained to using HDF4, should use HDF5 .