After a while staged as RC, we are proud to announce the final release of OPAM 1.1.0!

Thanks again to those who have helped testing and fixing the last few issues.

Important note

The repository format has been improved with incompatible new features; to account for this, the new repository is now hosted at, and the legacy repository at is kept to support OPAM 1.0 installations, but is unlikely to benefit from many package updates. Migration to will be done automatically as soon as you upgrade your OPAM version.

You're still free, of course, to use any third-party repositories instead or in addition.


NOTE: When switching from 1.0, the internal state will need to be upgraded. THIS PROCESS CANNOT BE REVERTED. We have tried hard to make it fault- resistant, but failures might happen. In case you have precious data in your ~/.opam folder, it is advised to backup that folder before you upgrade to 1.1.0.

Using the binary installer:

  • download and run

Using the .deb packages from Anil's PPA (binaries are currently syncing): add-apt-repository ppa:avsm/ppa apt-get update sudo apt-get install opam

For OSX users, the homebrew package will be updated shortly.

or build it from sources at :


For those who haven't been paying attention

OPAM is a source-based package manager for OCaml. It supports multiple simultaneous compiler installations, flexible package constraints, and a Git-friendly development workflow. OPAM is edited and maintained by OCamlPro, with continuous support from OCamlLabs and the community at large (including its main industrial users such as Jane-Street and Citrix).

The 'official' package repository is now hosted at, synchronised with the Git repository at, where you can contribute new packages descriptions. Those are under a CC0 license, a.k.a. public domain, to ensure they will always belong to the community.

Thanks to all of you who have helped build this repository and made OPAM such a success.


Too many to list here, see

For packagers, some new fields have appeared in the OPAM description format:

  • depexts provides facilities for dealing with system (non ocaml) dependencies
  • messages, post-messages can be used to notify the user eg. of licensing information, or help her troobleshoot at package installation.
  • available supersedes ocaml-version and os constraints, and can contain more expressive formulas

Also, we have integrated the main package repository with Travis, which will help us to improve the quality of contributions (see Anil's post).