## [6.1.0] - 2023-01-10

This is a bugfix release, which also adds some functionals.

### Fixed

- Memory allocation in xc-regression (!591)
- MGGA_C_REVSCAN was implemented incorrectly (#429)
- Missing comma in MGGA_XC_B97M_V (#437)

### Added

- HYB_GGA functionals: XC_RELPBE0
- HYB_MGGA functionals: XC_GAS22, XC_R2SCANH, XC_R2SCAN0, XC_R2SCAN50

### Removed

- GGA_X_HERMAN was incorrect: the functional is really a meta-GGA but its form was unclear and it seems numerically unstable (#399)

## [6.0.0] - 2022-10-14

This release changes the internal handling of derivatives in Libxc. Instead of the previous code where the same driver was used to evaluate all derivatives (controlled by an if statement in the innermost loop), in this version specialized versions of the Maple kernels are generated for all targeted numbers of derivatives as well as spin-polarized vs spin-unpolarized calculations. Moreover, array access has been improved, resulting in significant speedups on GPUs.

### Fixed

- LDA_C_KARASIEV and LDA_C_KARASIEV_MOD were implemented incorrectly (#382).

### Added

- GGA functionals: XC_B97_3C, X_PBE_GAUSSIAN, C_PBE_GAUSSIAN, X_PBE_MOD, X_NCAPR
- HYB_GGA functionals: XC_B3P86_NWCHEM
- MGGA functionals: C_TPSS_GAUSSIAN, C_CC, C_CCALDA, X_VCML, XC_VCML_RVV10
- HYB_MGGA functionals: XC_BR3P86
- functions to extract BibTeX reference keys from functionals

## [5.2.3] - 2022-05-16

### Fixed

- Fix compile issue with CUDA.

## [5.2.2] - 2022-02-01

### Fixed

- Some Maple sources had not been properly backported from the changed API in master which caused compile failures in 5.2.1 (#379)

## [5.2.1] - 2022-01-31

### Fixed

- Maple code in repository was incorrect for hyb_gga_x_cam_s12 (#372)
- Cleanup of reference handling in Fortran interface caused infinite loop (#374)

## [5.2.0] - 2022-01-21

### Fixed

- Clarified documentation of lda_x_erf and lda_x_yukawa (#362)
- C header should not depend on availability of derivatives in binaries (!522)
- Wrong flags with PGI compiler in CMake (#361)
- No automatic generation of sources at configure time; no recompilation necessary anymore when sources have not changed (#358)
- Interchanged parameter descriptions in wB97 style functionals (#363)
- lda_c_pmgb06 functional was missing a factor 1-z^2 (#360)
- Long lines in f90 include files (!517)
- Improved handling of null pointers in Fortran frontend (!515)
- hyb_mgga_xc_lc_tmlyp was tagged an exchange instead of an exchange-correlation functional (!527)

### Added

- MGGA functionals: x_ft98 (!512)
- Enforcement of Fermi curvature can now be turned off as a compile time option (#354)
- Components of mixed functionals like B3LYP can now be queried from C, Fortran and Python (#369)

## [5.1.7] - 2021-10-25

### Fixed

- References should not be updated automatically
- xc_version.h is now usable in Fortran
- Unnecessary external parameters removed from MGGA_X_RSCAN, MGGA_X_R2SCAN, and MGGA_X_R2SCANL

### Added

- LDA functionals: XC_CORRKSDT
- HYB_GGA functionals: X_CAM_S12G, X_CAM_S12H, XC_CASE21
- MGGA functionals: X_R2SCAN01, X_R4SCAN, X_RPPSCAN, C_RPPSCAN

## [5.1.6] - 2021-09-07

### Fixed

- Setting of _dev flag in pylibxc frontend
- CMake tests are now prefixed with the project name
- All elements of xc_dimensions are now properly initialized
- xc-run_testsuite no longer prints out garbage when run on a single functional

### Added

- GGA functionals: X_Q1D
- MGGA functionals: C_R2SCAN01, C_RREGTM, X_MCML, C_RMGGAC

## [5.1.5] - 2021-06-10

### Fixed

- Implementation of LDA_XC_BN05 which lacked 100% long-range exact exchange since it was introduced; functional is now called HYB_LDA_XC_BN05
- CMake did not generate XC_MICRO_VERSION macro

### Added

- LDA functionals: X_YUKAWA

## [5.1.4] - 2021-05-10

### Fixed

- Implementation of GGA_XC_LB07 which lacked 100% long-range exact exchange since it was introduced; functional is now called HYB_GGA_XC_LB07
- HYB_MGGA_X_JS18 was broken in 5.1.2 and 5.1.3 due to bug in port of Maple code from master branch
- HYB_GGA_XC_CAP0 erroneously had 75% of exact exchange instead of 25% since libxc 5.0.0
- MGGA_X_2D_PRHG07 was marked as a 3D functional instead of a 2D functional
- Libxc can now be compiled as energy-only without any derivatives
- More CUDA build fixes

### Added

- HYB_GGA functionals: XC_B3LYP3, XC_PBE_2X, XC_PBE38, XC_MCAM_B3LYP
- MGGA functionals: X_MTASK
- pylibxc can now be installed directly by CMake

## [5.1.3] - 2021-03-30

### Fixed

- Some fixes to CUDA compilation.
- HYB_GGA_XC_LC_BLYP_EA was not tagged as a hybrid functional.
- The automatically generated list of functionals on the webpage was missing hybrid functionals for the 5.1.x series.

## [5.1.2] - 2021-02-12

### Fixed

- A memory leak in libxcf90
- NaNs and overflows in GGA_C_OP_* introduced in 5.1.1 due to inconsistent screening of the density
- Missing CMake files from the tddft.org tarball

## [5.1.1] - 2021-02-09

### Added

- LDA functionals: C_W20
- GGA functionals: C_LYPR
- HYB_GGA functionals: XC_LC_BLYP_EA, XC_LC_BLYPR
- MGGA functionals: X_REGTM
- HYB_MGGA functionals: XC_LC_TMLYP

### Fixed

- A memory leak in the Fortran interface
- MGGA_X_REGTPSS was implemented incorrectly
- HYB_GGA_XC_LC_BLYP used a range separation parameter of 0.3 instead of 0.33; HYB_GGA_XC_LC_BLYP_EA corresponds to the earlier implementation
- Improvements to numerical stability of TPSS correlation functionals

## [5.1.0] - 2021-01-19

### Added

- Functions xc_reference() and xc_reference_doi() to get the up-to-date citation to Libxc
- GGA functionals: C_P86_FT, C_CCDF, C_P86_FT, K_LGAP, K_LGAP_GE, K_LKT, K_PBE2, K_PG1, K_RATIONAL_P, K_TFVW_OPT, K_VT84F, X_REVSSB_D, C_P86VWN, C_P86VWN_FT, X_PW91_MOD, X_ITYH_PBE, X_ITYH_OPTX
- HYB_GGA functionals: XC_CAMH_B3LYP, XC_WB97X_D3, XC_WHPBE0, XC_LC_BOP, XC_HFLYP, XC_B3P86_NWCHEM, XC_LC_PBEOP, XC_CAM_O3LYP
- MGGA functionals: C_B94, C_HLTAPW, C_M06_SX, X_R2SCAN, C_R2SCAN, X_R2SCANL, C_R2SCANL, K_CSK1, K_CSK4, K_CSK_LOC1, K_CSK_LOC4, K_GEA2, K_GEA4, K_L04, K_L06, K_PC07_OPT, K_PGSL025, K_RDA, X_HLTA, X_JK, X_MBR, X_MS2_REV, X_TH, C_KCISK
- HYB_MGGA functionals: XC_B94_HYB, X_M06_SX, XC_TPSS0

### Fixed

- Bugs in worker functions affecting all GGAs and meta-GGAs
- Several issues affecting kinetic energy functionals due to the use of inconsistent thresholds
- Incorrect definition of GGA_XC_KT3
- Incorrect implementation of GGA_X_OL1 and GGA_X_OL2
- Incorrect implementation of GGA_K_PERDEW
- Incorrect calculation of opposite-spin potentials for the ferromagnetic case
- Implementation of MGGA_X_MS2B still corresponded to the original preprint, not the final published version
- Numerical stability of range-separated functionals
- Several numerical overflow errors, affecting especially the SCAN family of functionals
- Incorrect definition of MGGA_C_B88, which was using B88 exchange instead of B86 exchange as supposed
- Missing minus sign in a coefficient of GGA_XC_HCTH_P76
- HYB_MGGA_X_PJS18 and HYB_MGGA_X_JS18 due to typo in the original publications
- Functional form of GGA_C_LM
- Bug in expint_E1 that had a huge effect on GGA_C_FT97

### Changed

- The renaming libxcf03 -> libxcf90 of 5.0.0 was reverted, as it proved to be problematic in downstream codes
- All numerical thresholds are now adjustable
- The threshold for the reduced gradient is now initialized based on the density threshold, instead of a hard-coded definition
- The CMake build system now generates pkgconfig files for the Fortran libraries

### Removed

- The GGA functionals LCGAU, LCGAU_CORE, and LC2GAU, since the implementation was not complete; the functionals have range-separation terms that cannot be described by the infrastructure in the version 5 series. The correct implementations are included in the version 6 branch

## [5.0.0] - 2020-04-06

### Added

- Framework to include worker functionals. These functionals are not intended to be use on their own, but as part of other functionals.
- LDA functionals: C_PMGB06, XC_BN05, XC_TIH, C_UPW92, C_RPW92, X_SLOC
- HYB_LDA functionals: XC_LDA0, XC_CAM_LDA0
- GGA functionals: X_LSPBE, X_LSRPBE, XC_KT3, XC_LB07, K_GDS08, K_GHDS10, K_GHDS10R, K_TKVLN, X_OPTB86B_VDW, C_ACGGAP, X_FD_LB94, X_FD_REVLB94, C_ZVPBELOC, X_B88_6311G, X_NCAP, X_ECMV92, C_CHACHIYO, C_PBE_VWN, X_S12G, X_LCGAU, X_LCGAU_CORE, X_LC2GAU, C_MGGAC
- HYB_GGA: XC_LC_WPBE_WHS, XC_LC_WPBEH_WHS, XC_LC_WPBE08_WHS, XC_LC_WPBESOL_WHS, XC_APF, XC_CAM_QTP_00, XC_CAM_QTP_02, XC_LC_QTP, XC_APBE0, XC_HAPBE, XC_WC04, XC_WP04, XC_CAM_PBEH, XC_CAMY_PBEH, XC_QTP17, XC_LC_BLYP, X_S12H, XC_BLYP35
- MGGA functionals: X_RTPSS, X_MS2B, X_MS2BS, X_MVSB, X_MVSBS, C_TM, X_BR89_1, X_BR89_EXPLICIT_1, C_REVM11, X_REGTPSS, X_2D_JS17, X_RSCAN, C_RSCAN, X_TLDA, X_EDMGGA, X_GDME_NV, X_GDME_0, X_GDME_KOS, X_GDME_VT, X_REVTM, C_REVTM, C_REVM06, X_SCANL, X_REVSCANL, C_SCANL, C_SCANL_RVV10, C_SCANL_VV10, X_MBRXH_BG, X_MBRXC_BG, X_TASK, X_MGGAC
- HYB_MGGA functionals: X_REVM11, XC_RCAM_B3LYP, X_JS18, X_PJS18, XC_B3LYP_MCM1, XC_B3LYP_MCM2, X_REVM06
- Worker functionals: LDA_K_GDS08_WORKER.
- Correction to the Fermi_D term in MGGA_C_M05, MGGA_C_M05_2X, and MGGA_C_DLDF to avoid divergences when the kinetic energy density is zero, but not the density. This is similar to the correction proposed in from JCP 127, 214103 (2007). The correction is controlled by the
`Fermi_D_cnst`

external parameter, and its default value is 1e-10. - Access to the internal parameters of several functionals. This is done using the same functions as for the external parameters.
- All functionals are now handled by Maple.
- Up to 4th-order for almost all functionals, and interface to access them.
- Printing of supported derivatives by the xc-info utility.
- New flag XC_FLAG_HAVE_ALL to indicate functionals that include all the currently available derivatives (exc, vxc, fxc, kxc, and lxc).
- Added the possibility of selectively disabling the compilation of vxc, fxc, kxc, and lxc to both Autotools and CMake build systems. By default kxc and lxc are not compiled. This allows for faster compilation times.
- Initial implementation of a GPU version of libxc

### Changed

- External parameters structure to include the name of the parameter. The name of the internal parameters is prepended with an underscore.
- Several functionals were modified to improve numerical stability. There are no more NaN or Infinities.
- Variable np is now size_t (8 bytes)
- Maple framework to generate the C code. In the new framework, the whole functional is handled by Maple, allowing the introduction of a unpolarized, ferromagnetic, and polarized case such that limiting cases are better handled.
- Integer type to c_int type in all Fortran 2003 interfaces.
- MGGA_C_TPSS to enforce z = tW/t <= 1 condition.
- XC_GGA_C_BCGP to XC_GGA_C_ACGGA, upon request by Antonio Cancio, keeping the old constant for backward compatibility.

### Fixed

- Missing terms in LDA_XC_KSDT and LDA_XC_GDSMFB.
- Incorrect parameter of GGA_C_GAPC.
- Incorrect definition of MGGA_C_KCIS.
- Incorrect definition of GGA_C_OPTC.

### Removed

- xc_mix_func function from public API.
- obsolete custom Fortran interface libxcf90 replaced with the 2003 version (libxcf03) that employs standard iso_c_binding to wrap the C functions to Fortran.

## [4.3.4] - 2019-03-04

### Fixed

- Bug in XC_HYB_GGA_XC_CAM_QTP_01. Functional erroneously had 81% LYP and 19% VWN5, whereas it is supposed to have 80% LYP and 20% VWN5 correlation.
- Bug in GGA_X_2D_B88. The value of beta was wrong.
- Bug in HSE12 and HSE12s. Range separation parameter were incorrect.

## Changed

- Authors list.

## [4.3.3] - 2019-02-11

### Fixed

- Missing pylibxc/version.py file from tarball.
- Incompatible code with Python 3 in setup.py.

## [4.3.2] - 2019-02-07

### Fixed

- Incorrect version number in Python interfaces.
- CMake build of Fortran interfaces. The build was failing due to non-existent file.
- NaN issues in MGGA_X_TM.

### Changed

- Handling of version number in Python interfaces.

## [4.3.1] - 2019-02-05

### Fixed

- Inclusion of xc_mgga_c_pkzb_set_params function in the public API, as this function does not exist anymore.

## [4.3.0] - 2019-01-30

### Added

- Several set_params functions to the API. These functions were removed from the API in version 4.0.0 and will be removed again in version 5.0.0, where they will be replaced by a more generic API.

### Fixed

- Several issues that prevented compilation on Windows.
- Inclusion of config.h in the xc.h header file.
- Incorrect SOVERSION with CMake builds.
- Use of non-POSIX function
`strdup`

. - Installation of Fortran module files with CMake.
- Installation of pkg-config
`.pc`

file with CMake.

### Deprecated

- Forrtran 90 bindings. These are replaced by the Fortran 2003 bindings and should be removed in version 5.0.0.

## [4.2.3] - 2018-07-02

### Added

- Installation of a libxc.pc file by CMake.
- Versioned shared library when buildbing with CMake.

### Fixed

- Timeout when generating the xc_func.h file with CMake.

## [4.2.2] - 2018-06-25

### Added

- Missing testsuite/CMakeLists.txt file from the tarball.

## [4.2.1] - 2018-06-06

### Added

- Compilation of Fortran interfaces with CMake.

## [4.2.0] - 2018-06-04

### Added

- GGA functionals: X_CHACHIYO, K_EXP4, K_PBE3, K_PBE4.
- HYB_MGGA: XC_B98.
- pkgconfig files for the Fortran interfaces.
- Missing regression tests for MGGA_X_BR89_EXPLICIT and LDA_C_GK72.

## [4.1.1] - 2018-05-08

### Fixed

- Missing python and CMake files from the tarball.

## [4.1.0] - 2018-05-07

### Added

- LDA functionals: C_GK72, C_KARASIEV, K_LP96.
- MGGA functionals: X_BR89_EXPLICIT, X_REVSCAN, C_SCAN_VV10, C_REVSCAN, C_REVSCAN_VV10.
- HYB_MGGA functionals: X_REVSCAN0.
- Optional Python interface.
- Functions to get the list of available functionals to the Fortran interfaces.

### Changed

- License from LGPL to the Mozilla Public License 2 (MPL2).
- CPP for Fortran sources macro, so that
`cpp -C -freestanding`

is used instead of`cpp -ansi`

. - XC_LDA_C_LP_A and XC_LDA_C_LP_A to XC_LDA_XC_LP_A and XC_LDA_XC_LP_A, as they are exchange-correlation functionals, keeping the old constant for backward compatibility.

### Fixed

- Bug in GGA_X_PBEPOW

## [4.0.5] - 2018-05-04

### Fixed

- Compilation with the PGI compiler.
- Compilation with GCC 6.3.0 on Power8.
- NaNs returned by MGGA_X_TM for large densities.
- Small bug in maple2C script.
- Bug in MGGA_X_MVS. This also affected HYB_MGGA_X_MVSH.

### Changed

- Improved documentation for range-separation parameters.

## [4.0.4] - 2018-01-17

### Fixed

- Incorrect XC_CORRELATION flag in the XC_LDA_K_ZLP, XC_LDA_X_RAE, and XC_GGA_XC_HLE16 functionals.
- Incorrect XC_EXCHANGE flag in the XC_GGA_C_SG4, XC_GGA_C_PBE_MOL, and XC_GGA_C_TM_PBE functionals.
- Incorrect XC_EXCHANGE_CORRELATION flag in the XC_MGGA_C_SCAN_RVV10 functional.
- Incorrect XC_FAMILY_MGGA family in the HYB_MGGA_XC_B0KCIS functional.

## [4.0.3] - 2017-11-20

### Fixed

- Generation of libxc_docs.txt file.

### Added

- Missing C to Fortran interface for
`xc_f90_nlc_coef`

.

## [3.0.1] - 2017-11-20

### Fixed

- Added missing MGGA_C_SCAN implementation (fix crash in 3.0.0).
- Uninitialized cam_omega, cam_alpha, and cam_beta parameters for LDA functionals.
- Flags defined in the Fortran 90 interface.
- Several references.
- Bugs in MGGA_X_MK00 and GGA_X_B86_R.
- Behavior for small tau in MGGA_XC_B97M_V and HYB_MGGA_XC_wB97M_V.
- Incorrect exchange mixing for HYB_GGA_X_CAP0.
- Description of several functionals.

### Added

- Missing C to Fortran interface for
`xc_f90_nlc_coef`

. - Missing interfaces for the set_params functions in the Fortran 90 interface.

## [4.0.2] - 2017-11-03

### Fixed

- Range-separation parameter in HSE functionals was not accessible through the
`xc_func_set_ext_params`

function. - Incorrect XC_CORRELATION flags in the XC_LDA_XC_1D_EHWLRG functionals.
- Example programs.
- Inconsistencies in the README files concerning the different build systems.

## [4.0.1] - 2017-09-28

### Added

- XC_FLAGS_DEVELOPMENT flag to XC_MGGA_C_KCIS, XC_HYB_MGGA_XC_B0KCIS, XC_HYB_MGGA_XC_MPW1KCIS, XC_HYB_MGGA_XC_MPWKCIS1K, XC_HYB_MGGA_XC_PBE1KCIS, and XC_HYB_MGGA_XC_TPSS1KCIS.

### Removed

- XC_FLAGS_DEVELOPMENT flag from MGGA_C_SCAN.

### Fixed

- Name of several Minnesota functionals to reflect the new interface.
- Missing braces in initialization of XC_MGGA_X_MN12_L, XC_HYB_MGGA_X_MN12_SX, XC_MGGA_X_MN15_L, and XC_HYB_MGGA_X_MN15.

## [4.0.0] - 2017-09-24

### Added

- LDA functionals: C_CHACHIYO, C_PK09, X_REL, XC_GDSMFB.
- GGA functionals: X_EB88, X_BEEFVDW, C_PBE_MOL, C_BMK, C_TAU_HCTH, C_HYB_TAU_HCTH, XC_BEEFVDW, K_ABSP3, K_ABSP4.
- HYB_GGA functionals: XC_LC_WPBE, XC_PBE_MOL0, XC_PBE_SOL0, XC_PBEB0, XC_PBE_MOLB0, XC_HSE12, XC_HSE12S, XC_HSE12, XC_HSE_SOL, XC_KMLYP.
- MGGA functionals: X_BMK, X_B00, C_SCAN, C_SCAN_RVV10, C_REVM06_L.
- HYB_MGGA functionals: X_TAU_HCTH.
- New generic function
`xc_func_set_ext_params`

to set external parameters. This replaces the functional specific functions`xc_*_set_par`

. - CMake based build system. It is not intended to replace the Autotools based build system, but rather to make it easier to integrate Libxc in projects that use CMake.
- New interface to hybrid Minnesota exchange functionals HYB_MGGA_X_M05, HYB_MGGA_X_M05_2X, HYB_MGGA_X_M06_2X, HYB_MGGA_X_M06_HF, HYB_MGGA_X_M06, HYB_MGGA_X_M08_SO, HYB_MGGA_X_M08_HF, HYB_MGGA_X_M11.
- Function
`xc_func_set_dens_threshold`

to set the threshold for small densities. All quantities are evaluated to zero when the density is smaller than this threshold. - New utility
`xc-threshold`

to evaluate the behavior of a given functional in the limit of small densities for a variety of test cases. This is particularly useful in choosing the appropriate density threshold to be set by`xc_func_set_dens_threshold`

. - File
**KNOWN_ISSUES**with a list of issues affecting some functionals that we are aware of. - XC_FLAGS_NEEDS_LAPLACIAN flag to signal MGGA functionals that depend on the laplacian of the density.
- New
**xc_funcs_removed.h**header file containing the ID’s of removed functionals for backward compatibility. - Several missing functions and flags from the Fortran interfaces.
- Functions to get the list of available functionals (
`xc_number_of_functionals`

,`xc_maximum_name_length`

,`xc_available_functional_numbers`

, and`xc_available_functional_names`

).

### Changed

- All functionals have been reimplemented using Maple to generate the corresponding C code.
- Updated default density thresholds for all functionals.
- Tests from the test suite are now separated by the derivative order (exc, vxc, and fxc). This allows to more easily identify the reason for failed tests and to set different tolerances for the different quantities.
- Split LDA_X into LDA_X and LDA_X_REL (see added functionals above). This replaces the external parameter that allowed to choose between the relativistic and non-relativistic versions of the functional.
- GGA_X_BGCP and GGA_C_BGCP to GGA_X_BCGP and GGA_C_BCGP, respectively, keeping the old constants for backward compatibility.
- MGGA_C_CC06 to MGGA_XC_CC06, as the functional includes an exchange part, keeping the old constant for backward compatibility.

### Removed

- Helper functionals that could be used in error instead of the true hybrid functional: MGGA_X_M05, MGGA_X_M05_2X, MGGA_X_M06_2X, MGGA_X_M06_HF, MGGA_X_M06, MGGA_X_M08_SO, MGGA_X_M08_HF, MGGA_X_M11.
- Exchange-correlation functional wrappers: HYB_MGGA_XC_M05, HYB_MGGA_XC_M05_2X, HYB_MGGA_XC_M06_2X, HYB_MGGA_XC_M06_HF, HYB_MGGA_XC_M06, HYB_MGGA_XC_M08_SO, HYB_MGGA_XC_M08_HF, HYB_MGGA_XC_M11. Replaced by e.g. the combination HYB_MGGA_X_M11+MGGA_C_M11.
- Functional specific functions
`xc_*_set_par`

to set external parameters. - Single precision version.

### Fixed

- Bug in HYB_GGA_XC_CAP0.

## [3.0.0] - 2016-04-21

### Added

- Micro version number to version function and version header file.
- Version_string function, which returns the version number in the following format:
`major.minor.micro`

- Fortran 2003 interface using the iso_c_bindings module.
- lda_vxc_fxc, gga_vxc_fxc, and mgga_vxc_fxc functions to Fortran 90 interface.
- LDA functionals: XC_ZLP, XC_KSDT.
- GGA functionals: X_LAMBDA_LO_N, X_LAMBDA_CH_N, X_LAMBDA_OC2_N, X_EV93, C_BGCP, X_BGCP, X_GAM, X_PBEFE, X_HCTH_A, C_GAM, C_PBEFE, C_OP_PW91, X_CAP.
- HYB_GGA functionals: XC_B3LYPs, XC_LRC_WPBEH, XC_LRC_WPBE, XC_WB97, XC_WB97X, XC_WB97X_V, XC_CAMY_B3LYP, XC_LC_VV10, XC_HPBEINT, XC_EDF2, XC_B3LYP5, XC_LCY_PBE, XC_LCY_BLYP, XC_CAP0.
- MGGA functionals: X_MBEEF, X_MBEEFVDW, X_MVS, X_SCAN, C_TPSSLOC, C_DLDF, X_MN15_L, C_MN15_L, C_MN15 XC_ZLP, XC_B97M_V.
- HYB_MGGA functionals: X_DLDF, X_MVSH, X_SCAN0, X_MN15, XC_M08_HX, XC_M08_SO, XC_WB97M_V, XC_B97_1p.

### Changed

- GGA_XC_HCTH_A to GGA_C_HCTH_A, as it does not include exchange (it uses a different form for exchange than the other functionals from the HCTH family), keeping the old constant for backward compatibility.
- GGA_C_VPBE to GGA_C_regTPSS, as that is the name used in the paper, keeping the old constant for backward compatibility.

### Removed

- Helper functionals that can be used in error instead of the true hybrid functional: GGA_XC_B97, GGA_XC_B97_1, GGA_XC_B97_2, GGA_XC_B97_K, GGA_XC_B97_3, GGA_XC_SB98_1a, GGA_XC_SB98_1b, GGA_XC_SB98_1c, GGA_XC_SB98_2a, GGA_XC_SB98_2b, GGA_XC_SB98_2c, GGA_XC_WB97, GGA_XC_WB97X, GGA_XC_WB97X_V, GGA_C_WB97X_D, MGGA_X_MN12_SX.

### Fixed

- Incorrect family for XC_HYB_MGGA_X_MS2H, which was incorrectly defined as a normal MGGA (XC_MGGA_X_MS2H).
- Bugs in GGA_C_HCTH_A, GGA_XC_TH_FL, GGA_XC_TH_FC, GGA_XC_TH_FCFO, GGA_XC_TH_FCO, GGA_XC_TH1, GGA_XC_TH2, GGA_XC_TH3, GGA_XC_TH4, MGGA_X_M11, MGGA_X_M11_L, HYB_MGGA_X_MS2H.

## [2.1.3] and [2.2.3] - 2016-04-21

### Fixed

- Bugs in GGA_X_N12, GGA_C_N12, GGA_C_N12_SX, all the GGA_X_HJS_*, GGA_X_VMT84_GE, HYB_GGA_X_N12_SX, all the HYB_GGA_XC_HJS_*, HYB_GGA_XC_O3LYP, HYB_GGA_XC_X3LYP.
- Bugs in second derivatives of GGA_X_B88, GGA_X_OPTB88_VDW, GGA_X_MB88, GGA_K_LLP, GGA_K_FR_B88, GGA_K_THAKKAR.
- Build with gcc 6.

## [2.1.2] and [2.2.2] - 2015-02-19

### Fixed

- Bug in unpolarized version of GGA_X_LB and GGA_X_LBM.
- Bugs in MGGA_C_REVTPSS, MGGA_C_M08_HX, MGGA_C_M08_SO, MGGA_C_M11, MGGA_C_M11_L.
- Missing variable initialization that could cause Libxc to return wrong mixing parameters for all HYB_GGA and HYB_MGGA.

## [2.1.1] and [2.2.1] - 2014-10-30

### Fixed

- Several bugs in the build system.
- Bugs in GGA_X_SOGGA11, HYB_GGA_X_SOGGA11_X, HYB_GGA_XC_CAM_B3LYP, HYB_GGA_XC_TUNED_CAM_B3LYP.

## [2.2.0] - 2014-03-21

### Changed

- Fortran bindings are now in a separate library (libxcf90).

## [2.1.0] - 2014-03-21

### Added

- New testsuite.
- xc_f90_functional_get_name and xc_f90_functional_get_number Fortran wrappers.
- GGA functionals: C_VPBE, C_PBEINT, C_ZPBESOL, C_ZPBEINT, C_Q2D, C_N12, C_N12_SX, X_LV_RPW86, X_N12, X_VMT_GE, X_VMT_PBE, X_VMT84_PBE, X_VMT84_GE, X_PBEINT, X_PBE_TCA, X_SFAT, X_AK13, X_PBE_MOL, X_Q2D, XC_OBLYP_D, XC_OPWLYP_D, XC_OPBE_D, K_MEYER, K_REVAPBE, K_APBEINT, K_REVAPBEINT, K_TFVW.
- MGGA functionals: C_M08_HX, C_M08_SO, C_M11, C_M11_L, C_MN12_L, C_MN12_SX, C_CC06, X_MS0, X_MS1, X_MS2, X_MS2H, C_REVTPSS, X_MN12_L, X_MN12_SX, X_MK00, X_MK00B, X_BLOC, X_MODTPSS, XC_OTPSS_D, XC_TPSSLYP1W.
- HYB_GGA functionals: X_N12_SX, XC_MPWLYP1M, XC_REVB3LYP.
- HYB_MGGA functionals: X_M11, X_M11_L, XC_CAMY_BLYP, XC_PWB6K, XC_PW6B95, XC_HYB_MGGA_XC_REVTPSSH, XC_HYB_MGGA_XC_TPSSH.
- Kxc for the following functionals GGA functionals: X_B86, X_B88, X_OPTB88_VDW, X_MB88, X_PBE, X_PBE_R, X_PBE_SOL, X_XPBE, X_PBE_JSJR, X_PBEK1_VDW, X_RGE2, X_APBE, X_PBEINT, X_PBE_TCA, X_WC, X_G96, X_RPBE, X_HTBS, X_PW86, X_PW91, X_AIRY, X_LAG, X_B86_MGC, X_BPCCAC, X_BAYESIAN, X_C09X, X_AM05, X_LG93, X_DK87_R1, X_DK87_R2, X_LV_RPW86, X_OPTX, X_SOGGA11, X_SSB_SW, X_VMT_PBE, X_VMT_GE, X_VMT84_PBE, X_VMT84_PBE, K_LLP, K_FR_B88, K_THAKKAR, K_APBE, K_REVAPBE, K_TW1, K_TW2, K_TW3, K_TW4, K_APBEINT, K_REVAPBEINT.
- Kxc for HYB_GGA_X_SOGGA11_X.

### Changed

- GGA_K_ABSR(1,2) to GGA_K_ABSP(1,2), keeping the old constants for backward compatibility.

## [2.0.3] - 2014-02-18

### Fixed

- Bugs in GGA_X_PBEA, MGGA_X_BR89, MGGA_X_BJ06, MGGA_X_TB09, MGGA_X_RPP09.
- Bug affecting second and third derivatives with spin-polarization of LDA_XC_TETER93.
- Non-initialized variable in the MGGA correlations, which could sometimes cause problems.

## [2.0.2] - 2013-07-10

### Fixed

- Bug in GGA_C_C09X.

- Non-initialized variables in LDA exchange that could sometimes cause problems.
- Some other small bugs.

## [2.0.1] - 2013-01-21

### Fixed

- Bug in all the B97-like GGA functionals.
- Bugs in MGGA_C_TPSS, MGGA_C_PKZB, MGGA_C_VSXC, MGGA_C_BC95.
- Numerical problems in the following functionals: GGA_C_WL, GGA_X_HJS, MGGA_C_OPTC, MGGA_C_TPSS, MGGA_C_PKZB.

## [2.0.0] - 2012-11-28

### Added

- Function and header file to get version number.
- LDA functionals: C_VWN1, C_VWN2, C_VWN3, C_VWN4, C_RC04.
- GGA functionals: C_OP, C_FT97, C_SPBE, X_SSB_SW, X_SSB, X_SSB_D, XC_HCTH_A, XC_B97_GGA1, XC_HCTH_P14, XC_HCTH_P76, XC_HCTH_407P, X_BPCCAC, C_LTA, C_revLTA, X_HJS.
- HYB_GGA functionals: XC_TUNED_CAM_B3LYP, XC_BHANDH, XC_CAM-B3LYP, XC_HSE
- MGGA: C_BC95, X_PKZB, C_PKZB, X_M05, C_M05, X_M05_2X, C_M05_2X, X_M06, C_M06, X_M06-L, C_M06-L, XC_M06-HF, C_M06-HF, X_M06-2x, C_M06-2x, X_M08_HX, X_M08_SO.
- HYB_MGGA functionals: XC_M05, XC_M05_2X, XC_BX88B95, XC_BX86B95, XC_PWX86B95, XC_BB1K, XC_MPW1B95, XC_MPWB1K, XC_X1B95, XC_XB1K.

### Changed

- Definition of tau in the metaGGAs. Now tau is the exact kinetic energy density (with the factor 1/2 included).
- Default interpolation of LDA_C_VWN.
- xc_hyb_gga_exx_coef function to xc_hyb_exx_coef.

### Fixed

- Several bugs.

## [1.2.0] - 2012-03-22

### Added

- GGA functionals: C_SOGGA11, X_SOGGA11, X_C09X, XC_TH1, XC_TH2, XC_TH3, XC_TH4, C_LM (spin-polarized), C_WI0, X_SOGGA, XC_MOHLYP, XC_MOHLYP2, X_AIRY, X_HTBS, etc.
- fxc to GGA_C_WI, GGA_C_WL, GGA_C_AM05, GGA_C_LYP, LDA_C_1D_CSC, etc.
- Regression tests.

### Changed

- xc_gga_exx_coef function to xc_hyb_gga_exx_coef.

### Removed

- LCA functionals.

### Fixed

- Several bugs.

## [1.1.0] - 2011-05-12

### Added

- New framework for GGA_C to make easier introducing new functionals.
- fxc to several metaGGAs.
- LDA functionals: C_GOMBAS, K_LP, K_TF
- GGA functionals: X_APBE, X_MB88, X_OL2, X_HERMAN, C_APBE, C_WL, K_THAKKAR, K_TW1, K_TW2, K_TW3, K_TW4, K_APBE, K_LC94, K_PERDEW, K_VSK, K_VJKS, K_ERNZERHOF, K_DK, K_OL2, K_OL1, K_FR_PW86, K_FR_B88, K_LLP, K_PEARSON, K_VW, K_GE2, K_GOLDEN, K_YT65, K_BALTIN, K_LIEB, K_ABSR1, K_ABSR2, K_GR, K_LUDENA, K_GP85.
- MGGA functionals: X_2D_PRHG07, X_2D_PRHG07_PRP10.

### Fixed

- Many bugs.
- Several functionals when the input density is zero.

## [1.0.0] - 2010-07-09

### Added

- LDA fucntionals: X, X_2D, X_1D, C_WIGNER, C_RPA, C_HL, C_GL, C_XALPHA, C_VWN, C_VWN_RPA, C_PZ, C_PZ_MOD, C_OB_PZ, C_PW, C_PW_MOD, C_OB_PW, C_2D_AMGB, C_2D_PRM, C_vBH, C_1D_CSC, C_ML1, C_ML2, XC_TETER93.
- GGA functionals: X_PBE, X_PBE_R, X_B86, X_B86_R, X_B86_MGC, X_B88, X_G96, X_PW86, X_PW91, X_OPTX, X_DK87_R1, X_DK87_R2, X_LG93, X_FT97_A, X_FT97_B, X_PBE_SOL, X_RPBE, X_WC, X_mPW91, X_AM05, X_PBEA, X_MPBE, X_XPBE, X_2D_B86_MGC, X_BAYESIAN, X_PBE_JSJR, X_2D_B88, X_2D_B86, X_2D_PBE, X_OPTB88_VDW, X_PBEK1_VDW, X_OPTPBE_VDW, X_RGE2, C_PBE, C_LYP, C_P86, C_PBE_SOL, C_PW91, C_AM05, C_XPBE, C_LM, C_PBE_JRGX, C_RGE2, XC_LB, XC_HCTH_93, XC_HCTH_120, XC_HCTH_147, XC_HCTH_407, XC_EDF1, XC_XLYP, XC_B97, XC_B97_1, XC_B97_2, XC_B97_D, XC_B97_K, XC_B97_3, XC_PBE1W, XC_MPWLYP1W, XC_PBELYP1W, XC_SB98_1a, XC_SB98_1b, XC_SB98_1c, XC_SB98_2a, XC_SB98_2b, XC_SB98_2c, XC_B3PW91.
- HYB_GGA functionals: XC_B3LYP, XC_B3P86, XC_O3LYP, XC_mPW1K, XC_PBEH, XC_B97, XC_B97_1, XC_B97_2, XC_X3LYP, XC_B1WC, XC_B97_K, XC_B97_3, XC_mPW3PW, XC_B1LYP, XC_B1PW91, XC_mPW1PW, XC_mPW3LYP, XC_SB98_1a, XC_SB98_1b, XC_SB98_1c, XC_SB98_2a, XC_SB98_2b, XC_SB98_2c.
- MGGA functionals: X_LTA, X_TPSS, X_M06L, X_GVT4, X_TAU_HCTH, X_BR89, X_BJ06, X_TB09, X_RPP09, C_TPSS, C_VSXC.
- LCA functionals: OMC, LCH.