What's Changed
* Never allow two-phase SOS. by ibell in https://github.com/CoolProp/CoolProp/pull/1837
* Allow list delimiter to be changed by ibell in https://github.com/CoolProp/CoolProp/pull/1838
* fixes in doxygen docu for fundamental derivative by DGSEM in https://github.com/CoolProp/CoolProp/pull/1842
* Document apply_simple_mixing_rule initialisation behaviour by m-allan in https://github.com/CoolProp/CoolProp/pull/1875
* Py38 by ibell in https://github.com/CoolProp/CoolProp/pull/1878
* Adding PC-SAFT EOS by zmeri in https://github.com/CoolProp/CoolProp/pull/1877
* fixed typo in getos() and else statement by tormec in https://github.com/CoolProp/CoolProp/pull/1885
* Fix uppercase-only fluid naming by alex-s-v in https://github.com/CoolProp/CoolProp/pull/1891
* Update init.py byte string in split for Py3.8 by dailyllama in https://github.com/CoolProp/CoolProp/pull/1896
* Update index.rst adding PropiedadesDeFluidos Tool by jfCoronel in https://github.com/CoolProp/CoolProp/pull/1903
* Update index.rst by HCSpin in https://github.com/CoolProp/CoolProp/pull/1906
* Fix second_partial_deriv example by nickmasonsmith in https://github.com/CoolProp/CoolProp/pull/1916
* Fix pcsaft flash by zmeri in https://github.com/CoolProp/CoolProp/pull/1913
* fix typos in pcsaft json by zmeri in https://github.com/CoolProp/CoolProp/pull/1921
* Fixed crash in PTflash_twophase::build_arrays by tobias-loew in https://github.com/CoolProp/CoolProp/pull/1881
* Allow nD-array input to PropsSI by jowr in https://github.com/CoolProp/CoolProp/pull/1932
* Update index.rst by MadsKirkFoged in https://github.com/CoolProp/CoolProp/pull/1947
* fixed typo with units for sigma by zmeri in https://github.com/CoolProp/CoolProp/pull/1949
* Update BaseObjects.py by whunter7 in https://github.com/CoolProp/CoolProp/pull/1957
* LibreOffice: Use pip for installing CoolProp python package by spinnau in https://github.com/CoolProp/CoolProp/pull/1993
* Fix cxx17 by ssg-aero in https://github.com/CoolProp/CoolProp/pull/1990
* Add Rust Wrapper by sgolle in https://github.com/CoolProp/CoolProp/pull/1977
* Fix cxx17 by ssg-aero in https://github.com/CoolProp/CoolProp/pull/2005
* Fix build on macOS by bryanwweber in https://github.com/CoolProp/CoolProp/pull/2008
* A minor correction in case of COOLPROP_OBJECT_LIBRARY=ON by dongkeun-oh in https://github.com/CoolProp/CoolProp/pull/2011
* Update index.rst for the C Wrapper by portyanikhin in https://github.com/CoolProp/CoolProp/pull/2050
* Fix typo in iQ description by Qi-Chu-woodside in https://github.com/CoolProp/CoolProp/pull/2056
* IF97 Backend Q and Phase Patch by henningjp in https://github.com/CoolProp/CoolProp/pull/2058
* Updated info for the C Wrapper by portyanikhin in https://github.com/CoolProp/CoolProp/pull/2062
* Included CoolPropJavascriptDemo by dvd101x in https://github.com/CoolProp/CoolProp/pull/2076
* Add functions to CoolPropLib by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2084
* Fix Rcomponent in calc_alpha0_deriv_nocache by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2101
* Add github action to build python wheels (including python 3.9 and 3.10) by jmarrec in https://github.com/CoolProp/CoolProp/pull/2097
* Cppcheck workflow by jmarrec in https://github.com/CoolProp/CoolProp/pull/2106
* Github Actions: add shared library and doxygen workflows. by jmarrec in https://github.com/CoolProp/CoolProp/pull/2098
* Lint: use automated tooling to reformat C++ and CMakeLists files by jmarrec in https://github.com/CoolProp/CoolProp/pull/2103
* Bump Catch 1 to Catch v3.0.0-preview4 by jmarrec in https://github.com/CoolProp/CoolProp/pull/2105
* Configure upload to pypi/testpypi by jmarrec in https://github.com/CoolProp/CoolProp/pull/2109
* Fix mac cibuildwheel by jmarrec in https://github.com/CoolProp/CoolProp/pull/2110
* Format macros + strip trailing whitespaces by jmarrec in https://github.com/CoolProp/CoolProp/pull/2108
* Add bound-check to setter and getter functions by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2107
* Fix mac sed by jmarrec in https://github.com/CoolProp/CoolProp/pull/2116
* Python bindings upload to (test)pypi fixes by jmarrec in https://github.com/CoolProp/CoolProp/pull/2118
* Missing a py37 build for Windows x64 + fix py38 win32 and py39 win32 by jmarrec in https://github.com/CoolProp/CoolProp/pull/2120
* Simplify CoolProp python bindings cibuildwheel by jmarrec in https://github.com/CoolProp/CoolProp/pull/2122
* Bump IF97 to included reverse T(P,H) patch [skip ci] by henningjp in https://github.com/CoolProp/CoolProp/pull/2132
* New functions for CoolPropLib by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2133
* AbstractState functions for CoolPropLib by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2135
* Corrected rho_ice route by replacing g_ice with dg_dp_Ice in Ice.cpp by Yaykhel in https://github.com/CoolProp/CoolProp/pull/2143
* Bump FindMathematica to most recent version by NotQuiteAwake in https://github.com/CoolProp/CoolProp/pull/2146
* improve PC-SAFT flash by zmeri in https://github.com/CoolProp/CoolProp/pull/2161
* Added info about PyFluids (3-party wrapper for Python) by portyanikhin in https://github.com/CoolProp/CoolProp/pull/2165
* Updated info about SharpProp (3-party wrapper for C) by portyanikhin in https://github.com/CoolProp/CoolProp/pull/2164
* Add fluid_param_string and get_JSONstring to cubic backend by friederikeboehm in https://github.com/CoolProp/CoolProp/pull/2134
* add PCSAFT page in docs by zmeri in https://github.com/CoolProp/CoolProp/pull/2176
* Prevent crashes near critical density due to saturation calc by msaitta-mpr in https://github.com/CoolProp/CoolProp/pull/2173
* Build the docs for v6.4.2 by jowr in https://github.com/CoolProp/CoolProp/pull/2191
New Contributors
* DGSEM made their first contribution in https://github.com/CoolProp/CoolProp/pull/1842
* m-allan made their first contribution in https://github.com/CoolProp/CoolProp/pull/1875
* zmeri made their first contribution in https://github.com/CoolProp/CoolProp/pull/1877
* tormec made their first contribution in https://github.com/CoolProp/CoolProp/pull/1885
* alex-s-v made their first contribution in https://github.com/CoolProp/CoolProp/pull/1891
* dailyllama made their first contribution in https://github.com/CoolProp/CoolProp/pull/1896
* jfCoronel made their first contribution in https://github.com/CoolProp/CoolProp/pull/1903
* HCSpin made their first contribution in https://github.com/CoolProp/CoolProp/pull/1906
* nickmasonsmith made their first contribution in https://github.com/CoolProp/CoolProp/pull/1916
* MadsKirkFoged made their first contribution in https://github.com/CoolProp/CoolProp/pull/1947
* ssg-aero made their first contribution in https://github.com/CoolProp/CoolProp/pull/1990
* sgolle made their first contribution in https://github.com/CoolProp/CoolProp/pull/1977
* dongkeun-oh made their first contribution in https://github.com/CoolProp/CoolProp/pull/2011
* portyanikhin made their first contribution in https://github.com/CoolProp/CoolProp/pull/2050
* Qi-Chu-woodside made their first contribution in https://github.com/CoolProp/CoolProp/pull/2056
* dvd101x made their first contribution in https://github.com/CoolProp/CoolProp/pull/2076
* friederikeboehm made their first contribution in https://github.com/CoolProp/CoolProp/pull/2084
* jmarrec made their first contribution in https://github.com/CoolProp/CoolProp/pull/2097
* Yaykhel made their first contribution in https://github.com/CoolProp/CoolProp/pull/2143
* NotQuiteAwake made their first contribution in https://github.com/CoolProp/CoolProp/pull/2146
* msaitta-mpr made their first contribution in https://github.com/CoolProp/CoolProp/pull/2173
**Full Changelog**: https://github.com/CoolProp/CoolProp/compare/v6.4.1...v6.4.2