Release v4.4.1

[4.4.1] - 2025-11-11

Fixed

• Proper version set in VERSION file (#1091)

Release v4.4.0

[4.4.0] - 2025-11-06

Added

• getIndexDigit function for inspecting specific index digits of an H3 index. (#1024, #1042)
• isValidIndex function (#1056, #1079)
• constructCell function (#1063, #1074, #1078)
• New H3_INDEX_INVALID, E_BASE_CELL_DOMAIN, E_DIGIT_DOMAIN, E_DELETED_DIGIT error codes and H3_ERROR_END (#1063, #1064, #1065)

Changed

• Updated minimum version of macOS in CI. (#1069)

Release v4.3.0

[4.3.0] - 2025-06-17

Added

• Added gridRing function, that works even if encountering pentagon distortion. (#1011, #1013, #1015)

Release v4.2.1

[4.2.1] - 2025-03-10

Fixed

• Fixed MSVC/WIN32 checks in CMake. (#981)
• Fixed potential memory leak in polygonStringToGeoPolygon (#976)

Changed

• Added arm64 tests in CI. (#975, #974)
• Faster isValidCell (#968)
• Moved ContainmentMode enum for polygonToCellsExperimental to h3api.h. (#958)

Release v4.2.0

[4.2.0] - 2024-12-04

Added

• Added experimental new algorithm for polygonToCells, called polygonToCellsExperimental, that supports more containment flags and is more memory-efficient (#785, #800, #947)
• h3 binary for shell scripts ready for use (#818, #826, #846, #923, #924, #931, #933)

Fixed

• Fixed compacting all or many resolution 1 cells (#919)

Changed

• compactCells internally uses int64 for array indexing. (#920)
• Reorganize tests into public / internal. (#762)
• Performance enhancement for aarch64, may improve other platforms (#790, #792, #852, #905, #913)
• clang-format upgraded to version 14. (#834)
• Fixed tests that incorrectly did not test resolution 15. (#820)
• Use CMAKE_INSTALL_LIBDIR when choosing where to install library files. (#819)

Release v4.1.0

[4.1.0] - 2023-01-18

Added

• Functions for cellToChildPos and childPosToCell (#719)

Fixed

• Fixed possible signed integer overflow in h3NeighborRotations (#707)
• Fixed possible signed integer overflow in localIjToCell (#706, #735)

Changed

• assert on defensive code blocks that are not already covered. (#720)
• clang-format upgraded to version 11. (#734)

Release v4.0.1

[4.0.1] - 2022-09-15

Fixed

• Changing an internal float to double improves the precision of geographic coordinate output (#652)
• Fixed compacting all children of a resolution 0 cell (#679)
• Fixed possible signed integer overflow in maxGridDiskSize (#686)
• Fixed possible use of uninitialized values in cellToVertex (#683, #690)
• Fixed possible out of bounds read in localIjToCell (#684)
• Fixed possible memory leak in compactCells (#685)
• Fixed possible out of bounds read in areNeighborCells (#677)
• Fixed possible memory leak in cellsToLinkedMultiPolygon (#673)

Changed

• Build script does not use toolchain file (#641)
• Removed a duplicated include preprocessor directive (#682)
• Improvements to the fuzzer suite and their automatic runs in CI (#671, #674, #687)
• Increased test coverage (#642)
• Added a fuzzer targetting internal algos.c functions (#675)

Release v4.0.0

[4.0.0] - 2022-08-23

Breaking changes

• Rename functions according to the terminology RFC (#622, #586, #571, #403, #466, #495, #466)
• Functions that can experience errors now have an H3Error return value. (#617, #586, #581, #551, #550, #509, #505, #507, #508, #503, #478, #468, #436, #359)
• Cell count parameters use int64_t instead of int.
• polygonToCells (previously polyfill) accepts a flags argument for future expansion. (#570)
• cellToLocalIj and localIjToCell accept a mode argument for future expansion. (#586)
• exactEdgeLength functions renamed to edgeLength (#639)

Fixed

• Fix polyfill bug when vertex latitude exactly matches cell center. (#603)
• A number of issues detected via unit tests and fuzzers were fixed. (#568, #562, #558, #559, #560, #430)
• polygonToCells returns an error if Infinity is passed in. (#636)

Changed

• The file CMakeTests.cmake is no longer included if ENABLE_TESTING is off. (#609)

Added

• Vertex mode and associated functions: (#422, #420, #417)
  • cellToVertex(cell, vertexNum)
  • cellToVertexes(cell, out)
  • vertexToLatLng(vertex, out)
  • isValidVertex(vertex)
• h3 CLI application. (#556, #497)

Other changes

• Generally use lng instead of lon
• Closed-form implementation of numHexagons
• A number of fuzzer harnesses are now included in the H3 core library. (#557, #553, #545, #433)
• Additional benchmarks are added and benchmarks are regularly run in CI. (#524, #518)

Release v4.0.0 Release Candidate 5

[4.0.0-rc5] - 2022-08-16

Breaking changes

• exactEdgeLength functions renamed to edgeLength (#639)

Fixed

• polygonToCells returns an error if Infinity is passed in. (#636)

Release v4.0.0 Release Candidate 4

[4.0.0-rc4] - 2022-07-25

Breaking changes

• distance* functions (distanceKm, etc) renamed to greatCircleDistance*. (#622)
• Error code E_MEMORY renamed to E_MEMORY_ALLOC. (#617)