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.

The work-in-progress release notes of a release candidate can be found on the Lean GitHub releases pages.

  1. Lean 4.19.0 (2025-04-02)
  2. Lean 4.18.0 (2025-04-02)
  3. Lean 4.17.0 (2025-03-03)
  4. Lean 4.16.0 (2025-02-03)
  5. Lean 4.15.0 (2025-01-04)
  6. Lean 4.14.0 (2024-12-02)
  7. Lean 4.13.0 (2024-11-01)
  8. Lean 4.12.0 (2024-10-01)
  9. Lean 4.11.0 (2024-09-02)
  10. Lean 4.10.0 (2024-07-31)
  11. Lean 4.9.0 (2024-07-01)
  12. Lean 4.8.0 (2024-06-05)
  13. Lean 4.7.0 (2024-04-03)
  14. Lean 4.6.0 (2024-02-29)
  15. Lean 4.5.0 (2024-02-01)
  16. Lean 4.4.0 (2023-12-31)
  17. Lean 4.3.0 (2023-11-30)
  18. Lean 4.2.0 (2023-10-31)
  19. Lean 4.1.0 (2023-09-26)
  20. Lean 4.0.0 (2023-09-08)
  21. Lean 4.0.0-m5 (2022-08-22)
  22. Lean 4.0.0-m4 (2022-03-27)
  23. Lean 4.0.0-m3 (2022-01-31)
  24. Lean 4.0.0-m2 (2021-03-02)
  25. Lean 4.0.0-m1 (2021-01-04)