The changes fall into the following categories:

- Implementation of the IAU 2012 definition of the astronomical unit (au). Not only has this constant been updated, but also
- all derived quantities are evaluated via the appropriate formulas, and
- all documentation now uses the appropriate symbols for the unit, for example, 1 au and 2.3 au/day.

- Update to PVSTAR to make it consistent with the version of STARPV that was updated in the previous release.
- Other minor typographical corrections to various routines.

- The IAU 2012 value of the astronomical unit (au) is now implemented in these six routines:
- iau_APCS
- iau_LDN
- iau_PMPX
- iau_PVSTAR
- iau_STARPM
- iau_STARPV
- An expression (sqrt(1-x)-1), where x is usually tiny, has been replaced with (-x/(sqrt(1-x)+1) to improve numerical precision in iau_PVSTAR.
- Check values in the validation program t_sofa_f have been updated due to the change in the astronomical unit.
- The SOFA Astrometry Tools cookbook sofa_ast_f.pdf:
- In the table on page 22 there is a change of +1×10
^{-7}seconds in RA for three results when compared to using the previous value for the au. These cases are repeated on the next 2 pages. - The listing of the relativistic version of the routine iau_PMPX in the Appendix has been updated on page 77 with the required changes for the au.

- In the table on page 22 there is a change of +1×10

- The astronomical unit (au) has been updated in the sofam.h include file and all constants that are derived from the au have been replaced by the appropriate formulas.
- An expression (sqrt(1-x)-1), where x is usually tiny, has been replaced with (-x/(sqrt(1-x)+1) to improve numerical precision in iauPvstar.
- Check values in the validation program t_sofa_c have been updated due to the change in the astronomical unit.
- The SOFA Astrometry Tools cookbook sofa_ast_c.pdf:
- In the table on page 20 there is a change of +1×10
^{-7}seconds in RA for three results when compared to using the previous value for the au. These cases are repeated on the next three pages.

- In the table on page 20 there is a change of +1×10