[netcdf-java] netcdf-java long data type?

*http://www.unidata.ucar.edu/software/netcdf-java/ says:
/Features not yet available/*/: Writing to netCDF-3 is supported, but new features in the CDM, e.g. groups, structures, the long data type are not available yet./

Why is the long data type not currently supported and when can I expect it to be?

Thanks,
Dan Wilkinson