The Lean Language Reference

Release Notes🔗

This section provides release notes about recent versions of Lean. When updating to a new version, please read the corresponding release notes. They may contain advice that will help you understand the differences with the previous version and upgrade your projects.

  1. Lean 4.33.0-rc1 (2026-07-15)
  2. Lean 4.32.2 (2026-07-28)
  3. Lean 4.32.1 (2026-07-22)
  4. Lean 4.32.0 (2026-07-13)
  5. Lean 4.31.0 (2026-06-13)
  6. Lean 4.30.0 (2026-05-26)
  7. Lean 4.29.1 (2026-04-14)
  8. Lean 4.29.0 (2026-03-27)
  9. Lean 4.28.1 (2026-04-14)
  10. Lean 4.28.0 (2026-02-17)
  11. Lean 4.27.0 (2026-01-24)
  12. Lean 4.26.0 (2025-12-13)
  13. Lean 4.25.1 (2025-11-18)
  14. Lean 4.25.0 (2025-11-14)
  15. Lean 4.24.0 (2025-10-14)
  16. Lean 4.23.0 (2025-09-15)
  17. Lean 4.22.0 (2025-08-14)
  18. Lean 4.21.0 (2025-06-30)
  19. Lean 4.20.0 (2025-06-02)
  20. Lean 4.19.0 (2025-05-01)
  21. Lean 4.18.0 (2025-04-02)
  22. Lean 4.17.0 (2025-03-03)
  23. Lean 4.16.0 (2025-02-03)
  24. Lean 4.15.0 (2025-01-04)
  25. Lean 4.14.0 (2024-12-02)
  26. Lean 4.13.0 (2024-11-01)
  27. Lean 4.12.0 (2024-10-01)
  28. Lean 4.11.0 (2024-09-02)
  29. Lean 4.10.0 (2024-07-31)
  30. Lean 4.9.0 (2024-07-01)
  31. Lean 4.8.0 (2024-06-05)
  32. Lean 4.7.0 (2024-04-03)
  33. Lean 4.6.0 (2024-02-29)
  34. Lean 4.5.0 (2024-02-01)
  35. Lean 4.4.0 (2023-12-31)
  36. Lean 4.3.0 (2023-11-30)
  37. Lean 4.2.0 (2023-10-31)
  38. Lean 4.1.0 (2023-09-26)
  39. Lean 4.0.0 (2023-09-08)
  40. Lean 4.0.0-m5 (2022-08-22)
  41. Lean 4.0.0-m4 (2022-03-27)
  42. Lean 4.0.0-m3 (2022-01-31)
  43. Lean 4.0.0-m2 (2021-03-02)
  44. Lean 4.0.0-m1 (2021-01-04)