Version 3.0 - Code only

(15th May 2011)
Consists of approximately 166 functions.

Major improvements

48-term density equation introduced (intended for use by observational, theoretical oceanographers and ocean modellers). The use of a single density equation will ensure a unified field.
the Absolute Salinity Anomaly takes into account evaporation and dilution.
freezing temperatures
isobaric melting enthalpy and isobaric evaporation enthalpy
Main changes

all functions which have in-situ temperature t as the input temperature now end in "_t_exact"
all functions which have Conservative Temperature CT as the input temperature and which are directly evaluated using the Gibbs function now end in "_CT_exact" (in version 2 they ended in "_CT")
all functions which have Conservative Temperature CT as the input temperature and were based on the 25 term density equation have been replaced with the 48 term density function.
The "_CT25" ending has been dropped.
the 25 term density equation has been removed.
all functions which have Conservative Temperature CT as the input temperature but use the 48 term density function can be called either with "_CT" at the end of their function names or without this ending. This point is the biggest change as many of these function names in version 2 used in-situ temperature (t) as the input temperature and the relied on the Gibbs function.
Geostrophic streamfunctions now allow the user to define a reference pressure, and the options for the interpolation style and interpolated bottle resolution has been removed.
Bug fixes

Version 3.04 - Code only

(20th December, 2013)
Added

seawater properties at the freezing temperature
thermodynamic properties of ice Ih
thermodynamic interaction between ice Ih and seawater
thermodynamic interaction between sea ice and seawater
dissolved gasses
gsw_CT_from_enthalpy and gsw_CT_from_enthalpy_exact
gsw_CT_first_derivatives_wrt_t_exact
gsw_enthalpy_first_derivatives_wrt_t_exact
gsw_t_deriv_chem_potential_water_t_exact
Renamed gsw_streric_height to gsw_geo_strf_steric_height

Renamed gsw_CT_freezing to gsw_CT_freezing_poly

Renamed gsw_t_freezing to gsw_t_freezing_poly

Renamed gsw_brineSA_CT to gsw_brineSA_CT_poly

Renamed gsw_brineSA_t to gsw_brineSA_t_poly

This is the final version where functions based on the 48-term expression for density that end in "_CT" are supported

Version 3.03 - Code only

Added

isentropic compressibility (kappa) for the 48-term equation of state.
gsw_rho_first derivatves and gsw_rho_first derivatves_CT_exact.
gsw_alpha_on_beta and gsw_alpha_on_beta_CT_exact.
gsw_t_from_pt0
gsw_t_from_entropy
gsw_adiabatic_lapse_rate_from_CT.
gsw_deltaSA_from_rho_t_exact.
Remaned gsw_entropy_t_exact to gsw_entropy_from_t, and added ths inverse function (gsw_t_from_entropy)

Renamed gsw_adiabatic_lapse_rate_t_exact to gsw_adiabatic_lapse_rate_from_t

Version 3.02 - Code only

(20th November, 2012)
Improved computation efficiency.

Minor bug fixes.

Version 3.01 - Code only

(14th November 2011)
Bug fix in gsw_SA_Sstar_from_SP (line 182).

Version 2 - Code only.

(18th October 2010)
Consists of approximately 100 functions

Introduced

the new naming structure for conversion functions, gsw_X_from_Y
Streamfunctions
water column properties
neutral and non-linear properties
planet Earth properties
derivatives of enthalpy, entropy, Conservative temperature and potential temperature
25 term density equation (intended for modellers)
Major changes

Absolute Salinity Anomaly extended to cover all areas of the ocean
Bug fixes

Version 1 - Code only.

(1st January 2009)

Consists of approximately 16 functions

Introduction of the Absolute Salinity Anomaly