# Using This Guide with HDF5 Release 1.8.x

Several sections describing new features introduced with HDF5 Release 1.8.x have been added to this HDF5 User's Guide:

- N-bit and scale/offset filters, in the chapter “HDF5 Datasets”
- New Error API functions, H5E, in the chapter “HDF5 Error Handling”
- Metadata caching, in the chapter “Special Topics”

Other work to bring the Guide up to date with the HDF5 Release 1.8.x series remains to be done. Readers should keep the following things in mind:

- Principles and models described in the Guide remain applicable to the 1.8.x series.
- The function summaries in several chapters are incomplete for the 1.8.x series. Refer to the HDF5 Reference Manual for complete lists.
- Code examples use function syntax from the 1.6.x release series. See the note below regarding the use of 1.6.x syntax with a 1.8.x version of the HDF5 Library.

### Using 1.6.x syntax with the 1.8.x library

HDF5 Release 1.8.x includes an API compatibility feature that enables codes written with 1.6.x function syntax to be compiled against and linked with an HDF5 Release 1.8.x Library.

When working with an installed version of the HDF5 Library that has been built with default settings, use the `h5cc` script and the `-DH5_USE_16_API` flag to compile and link your C program as follows:

        h5cc <other_instructions> -DH5_USE_16_API . . .

A comparable script, `h5fc`, is provided for Fortran programs.

For further details or alternate approaches, see “API Compatibility Macros in HDF5.”