• Request compressed responses when querying the release index, shrinking the transfer from ~3.7MB to ~150KB.

4.2.4 - 2026-08-25

• elan install/elan toolchain install now report an already-installed toolchain as such and exit with code 0 instead of failing with '...' is already installed.
• Fix panic in elan toolchain gc when a toolchain directory listed in ~/.elan/toolchains does not resolve to an existing directory, e.g. after deleting a toolchain manually.

4.2.3 - 2026-06-08

• Don't abort toolchain installation when the elan self-update check fails (e.g. due to a network error); emit a warning and continue instead.

4.2.2 - 2026-05-28

• Fix detection of being inside a toolchain directory on Windows when the path is reported with a lowercase drive letter (#199).
• Replace leftover Rust term "crate" with "package" in elan toolchain help link (#175).
• Error instead of silently downloading the default toolchain when lean-toolchain is unparseable or points to a path without bin/lean (#197).

4.2.1 - 2026-03-18

• Fix combining elan override with new path-based toolchains.

4.2.0 - 2026-02-25

• Resume interrupted downloads via HTTP Range headers. When a download fails due to a network error, elan now automatically retries once, resuming from where it left off. Also adds a stall timeout (30s at <10 bytes/sec) so downloads no longer hang indefinitely on unreliable connections.
• Support absolute and relative toolchain paths in lean-toolchain etc.
• Print a notice when a directory override (set via elan override set) is active, helping catch stale overrides that may cause confusing build failures. Can be suppressed with ELAN_NO_OVERRIDE_NOTICE=1.

4.1.2 - 2025-05-26

• Ignore errors when writing to .elan/known-projects, e.g. when it is read-only.

4.1.1 - 2025-04-30

• Fix installing from leanprover/lean4-pr-releases, which are not part of release.lean-lang.org.

4.1.0 - 2025-04-30

• Fetch releases and assets from release.lean-lang.org instead of parsing GitHub HTML. Makes toolchain URL resolution robust against future GitHub changes and enables use of the beta channel to refer to the latest RC release. Also allows for distinguishing between non-existing releases and non-existing assets for a release.

4.0.1 - 2025-04-18

• Fix selection of most recent stable toolchain when offline

4.0.0 - 2025-01-30

• Revamp toolchain resolution and storage
  • Toolchain references are now always resolved to a fixed <owner>/<repo>:<version> format before downloading, resolving the issue of having the same toolchain installed as e.g. stable, v4.9.0, and leanprover/lean4:v4.9.0 and ensuring that e.g. stable has the same meaning for everyone at a given point in time. Elan will automatically uninstall toolchains under now-unreachable names.
  • Accordingly, elan update has been removed as updates of non-fixed toolchains are now implicit.
  • This also fixes lake +stable new ... putting an unadvisable leanprover/lean4:stable reference in lean-toolchain.
  • The configured default toolchain name is stored unresolved (and not immediately installed) but is resolved before every use. This also means that passing --default-toolchain none to the elan install script is not necessary anymore to speed up installation.
  • In case of a network error resolving a toolchain, elan falls back to the previous resolution if any and prints a warning.
  • The update-hashes/ directory is not used anymore, deleting toolchains/ or direct subdirectories does not break elan anymore.
• More useful download and installation info messages
• Experimental elan toolchain gc command. See elan toolchain gc --help for documentation. lean-toolchain files will only be known to the GC after being used at least once with this version of elan.

3.1.1 - 2024-02-22

• Fix update check

3.1.0 - 2024-02-19

• Fix partial toolchains potentially being left in place when unpacking is aborted (#121)
• Check for elan updates during toolchain downloads (#122)

3.0.0 - 2023-09-08

• Default to stable toolchain again in time for first Lean 4 stable release (#104)

2.0.1 - 2023-07-24

• Fix download progress display on Windows (#101)

2.0.0 - 2023-07-03

• Support toolchain reference <origin>:lean-toolchain that refers to the toolchain referred to by the contents of the given GitHub file (#99)

• Default to Lean 4 (#98)

1.4.6 - 2023-06-10

• Avoid dependency on the VC++ Redistributable on Windows (#97)

1.4.5 - 2023-04-26

• Fix self update on Apple Silicon (only?) (#78)

1.4.4 - 2023-04-24

• Update dependencies

1.4.3 - 2023-04-24

• Avoid setting (DY)LD_LIBRARY_PATH (#90)

1.4.2 - 2022-09-13

• Fix downloading Lean releases again

1.4.1 - 2022-04-15

Added

• Actual support for ARM64 macOS (M1)

1.4.0 - 2022-03-28

Added

• Support for ARM64 macOS (M1)

1.3.1 - 2021-11-01

Changed

• Update dependencies

1.3.0 - 2021-11-01

Added

• Support for zstd-compressed tarballs

1.2.0 - 2021-10-19

Added

• Support for ARM64 Linux

1.1.2 - 2021-10-15

Changed

• Remove another "press any key to exit"

1.1.1 - 2021-10-15

Changed

• Remove "press any key to exit" step from Windows installation not needed for VS Code or PowerShell method

1.1.0 - 2021-10-08

Added

• Add lake Lean 4 executable

1.0.8 - 2021-09-10

Changed

• Fix elan self update on not-Linux, again

1.0.7 - 2021-08-16

Changed

• Default to respective toolchain inside of ~/.elan (#36)

1.0.6 - 2021-05-25

Changed

• Fix elan self update on not-Linux and build from cmdline

1.0.5 - 2021-05-25

Changed

• Run extension-less tools such as leanc using sh on Windows (and hope for the best...)

1.0.4 - 2021-05-24

Changed

• Update suggestion when no default toolchain is configured (#31)
• Fix elan show when no default toolchain is configured (#33)

1.0.3 - 2021-04-30

Changed

• Fix elan self update download URL on Linux

1.0.2 - 2021-04-28

Changed

• Fix installation from non-default repos

1.0.1 - 2021-04-28

Changed

• Fix updating channels from non-default repos (e.g. leanprover/lean4:nightly) This change affects the store location of such toolchains, so you will have to re-install them first.

  $ elan toolchain uninstall leanprover-lean4-nightly
  $ elan toolchain install leanprover/lean4:nightly
  

1.0.0 - 2021-04-17

• Move to leanprover/elan

0.11.0 - 2021-03-09

Changed

• Make elan a static executable on Linux
• Improve leanpkg.toml error handling (#26)
• Make downloaded files read-only (on Linux/macOS) (#27)

0.10.3 - 2021-01-15

Changed

• Hopefully fix Lean 4 leanpkg on Windows

0.10.2 - 2020-05-11

Changed

• Hopefully actually restore elan toolchain link functionality

0.10.1 - 2020-05-11

Changed

• Hopefully restore elan toolchain link functionality

0.10.0 - 2020-05-08

Changed

• Accept (almost) arbitrary release tag names in addition to version numbers

0.9.0 - 2020-05-07

Added

• Add leanc, leanmake Lean 4 executables

0.8.0 - 2020-03-06

Changed

• stable/nightly now refer to leanprover-community, Lean's community fork. This includes the toolchain installed by default (stable).

0.7.5 - 2019-03-21

Changed

• Fix release lookup once more with feeling

0.7.4 - 2019-03-20

Changed

• Fix self-update always triggering

0.7.3 - 2019-03-20

Changed

• Fix lookup of latest Github release of both Lean and elan

0.7.2 - 2019-01-15

Changed

• Fix name check in elan toolchain link (#17)

0.7.0 - 2018-09-16

Added

• elan will now warn if there are other Lean installations in the PATH before installing

Changed

• Fix mtimes not being restored from installation archives
• Fix invoking leanpkg on Windows

0.6.0 - 2018-08-01

Added

• Version specifiers can now point to custom forks of Lean, such as khoek/klean:3.4.1 (#8)

0.5.0 - 2018-04-20

Changed

• An explicit version passed to a proxy command like in leanpkg +nightly build will now be installed automatically when necessary
• Full toolchain names and their directories do not mention the operating system (the "target triple", to be exact) any more. You may want to delete your old toolchains from ~/.elan/toolchains to save space.

[0.4.0 - 2018-04-17]

Changed

• leanpkg.toml and lean-toolchain files can now reference custom toolchains (those added by elan toolchain link)

[0.3.0] - 2018-04-11

Added

• leanchecker proxy

[0.2.0] - 2018-04-11

Added

• curl | sh installation and instructions

Changed

• Fix elan toolchain link (#1)
• Fix self-update
• De-rustify docs

[0.1.0] - 2018-04-10

Minimum viable product release

Added

• Building on Rustup's code, implement installing and managing Lean toolchains
• Have leanpkg.toml files override the Lean version