The following GRIBEX Fortran interface is no longer present in the GRIB API. You will have seen from the GRIB API Fortran 90 interface that the information contained in the GRIB message can be accessed through alphanumeric keys.
In your Fortran code, you will have to explicitly name the keys that you are using. The tables below will help you find the key names corresponding to the "old" GRIB1 header section elements.
These tables include the GRIB API Coded key names and also Recommended GRIB API key names. You should use the latter.