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 4.34.0 (2026-09-14)
  2. Lean 4.33.1 (2026-08-21)
  3. Lean 4.33.0 (2026-08-10)
  4. Lean 4.32.2 (2026-07-28)
  5. Lean 4.32.1 (2026-07-22)
  6. Lean 4.32.0 (2026-07-13)
  7. Lean 4.31.0 (2026-06-13)
  8. Lean 4.30.0 (2026-05-26)
  9. Lean 4.29.1 (2026-04-14)
  10. Lean 4.29.0 (2026-03-27)
  11. Lean 4.28.1 (2026-04-14)
  12. Lean 4.28.0 (2026-02-17)
  13. Lean 4.27.0 (2026-01-24)
  14. Lean 4.26.0 (2025-12-13)
  15. Lean 4.25.1 (2025-11-18)
  16. Lean 4.25.0 (2025-11-14)
  17. Lean 4.24.0 (2025-10-14)
  18. Lean 4.23.0 (2025-09-15)
  19. Lean 4.22.0 (2025-08-14)
  20. Lean 4.21.0 (2025-06-30)
  21. Lean 4.20.0 (2025-06-02)
  22. Lean 4.19.0 (2025-05-01)
  23. Lean 4.18.0 (2025-04-02)
  24. Lean 4.17.0 (2025-03-03)
  25. Lean 4.16.0 (2025-02-03)
  26. Lean 4.15.0 (2025-01-04)
  27. Lean 4.14.0 (2024-12-02)
  28. Lean 4.13.0 (2024-11-01)
  29. Lean 4.12.0 (2024-10-01)
  30. Lean 4.11.0 (2024-09-02)
  31. Lean 4.10.0 (2024-07-31)
  32. Lean 4.9.0 (2024-07-01)
  33. Lean 4.8.0 (2024-06-05)
  34. Lean 4.7.0 (2024-04-03)
  35. Lean 4.6.0 (2024-02-29)
  36. Lean 4.5.0 (2024-02-01)
  37. Lean 4.4.0 (2023-12-31)
  38. Lean 4.3.0 (2023-11-30)
  39. Lean 4.2.0 (2023-10-31)
  40. Lean 4.1.0 (2023-09-26)
  41. Lean 4.0.0 (2023-09-08)
  42. Lean 4.0.0-m5 (2022-08-22)
  43. Lean 4.0.0-m4 (2022-03-27)
  44. Lean 4.0.0-m3 (2022-01-31)
  45. Lean 4.0.0-m2 (2021-03-02)
  46. Lean 4.0.0-m1 (2021-01-04)