4.2. Downloading Open MPI

Open MPI is generally available two ways:

  1. As source code.

    • The best place to get an official Open MPI source code distribution is from the main Open MPI web site.

    • Downstream Open MPI packagers (e.g., Linux distributions) sometimes also provide source code distributions. They may include additional patches or modifications.

      Consult your favorite downstream packager for more details.

    Caution

    Do not download an Open MPI source code tarball from GitHub.com. The tarballs automatically generated by GitHub.com are incomplete and will not build properly.

    GitHub.com-generated tarballs are not official Open MPI releases.

  2. As binary packages.

    • The Open MPI community does not provide binary packages on the main Open MPI web site.

    • Various downstream packagers (e.g., Linux distributions, Homebrew, MacPorts, etc.) do provide pre-built, binary packages for Open MPI.

      Consult your favorite downstream packager for more details.

Most of the remaining pages of this part of the documentation deal with installing Open MPI from source; the next section covers detecting new releases programmatically.

4.2.1. Detecting new releases programmatically

Packagers, CI systems, and automated agents can discover new Open MPI releases without scraping the download web pages: the Open MPI web site publishes machine-readable files that are generated from the same data as the download pages, so they always agree with them.

  • The JSON documents are the recommended interface. They carry the most information: every release and prerelease in every series, release dates, and each release’s downloadable files with URLs, sizes, and checksums.

  • The plain-text files are a convenience for simple checks (e.g., in a shell script) that only need the latest version number.

  • The Atom feeds are a convenience for subscribing to release announcements in feed readers or chat/email integrations. They carry less information than the JSON documents (e.g., no checksums).

These files cover Open MPI v4.1.0 and later (i.e., the v4.1 and later release series). Releases older than that are ancient: they are still available from the Open MPI web site’s download pages, but they are not listed in these files, and their release series do not have per-series files.

4.2.1.1. JSON documents

Two JSON documents are available:

The index looks like this (abridged):

{
    "schema_version": 1,
    "project": "Open MPI",
    "current_series": "5.0",
    "latest_release": "5.0.11",
    "series": [
        {
            "series": "6.0",
            "branch": "v6.0.x",
            "latest_release": null,
            "latest_prerelease": "6.0.0rc2",
            "releases": [],
            "prereleases": ["6.0.0rc2", "6.0.0rc1"],
            "web_page_url": "https://www.open-mpi.org/software/ompi/v6.0/",
            "download_url_prefix": "https://download.open-mpi.org/release/open-mpi/v6.0/",
            "details_url": "https://www.open-mpi.org/software/ompi/v6.0/downloads/releases.json"
        },
        {
            "series": "5.0",
            "branch": "v5.0.x",
            "latest_release": "5.0.11",
            "latest_prerelease": null,
            "releases": ["5.0.11", "5.0.10", "...", "5.0.0"],
            "prereleases": [],
            "...": "..."
        }
    ]
}

Top-level fields of the index:

  • schema_version: the version of this format; see below.

  • project: always Open MPI.

  • current_series: the release series that the Open MPI community currently recommends (e.g., 5.0). Note that newer series may exist (e.g., a series that only has prereleases so far).

  • latest_release: the latest release of current_series.

  • series: an array with one entry per release series, newest series first.

Each entry in series (and the top level of the per-series document) contains:

  • series: the series name, A.B (no leading v).

  • branch: the Open MPI Git branch the series is released from.

  • latest_release / latest_prerelease: the newest release / prerelease in the series, or null if there is none.

  • releases / prereleases: every release / prerelease version in the series, newest first. Prereleases are typically removed from prereleases once the corresponding final release is out.

  • web_page_url: the human-readable download page for the series.

  • download_url_prefix: the URL prefix of the series’ downloadable files.

  • details_url: the URL of the per-series JSON document.

The per-series document adds a release_details array, with one entry for every version in prereleases and then releases (each newest first):

{
    "version": "5.0.11",
    "prerelease": false,
    "release_date": "2026-09-16T22:13:00Z",
    "release_unix_time": 1789596780,
    "files": [
        {
            "name": "openmpi-5.0.11.tar.bz2",
            "url": "https://download.open-mpi.org/release/open-mpi/v5.0/openmpi-5.0.11.tar.bz2",
            "size": 45250787,
            "sha256": "e668a3c4acd50c41dc204c8a6dd98a611e0f26af89cf677577fa9be8a2698003",
            "sha1": "02fa478148ebe764013bcc118930681952b89a31",
            "md5": "284035e88115c3da0f9812ce1141232f"
        }
    ]
}

  • release_date / release_unix_time: when the release was published, as an ISO 8601 UTC timestamp and as seconds since the Unix epoch.

  • files: every downloadable file of the release (source tarballs, SRPMs, etc.), sorted by name. size is in bytes. sha256, sha1, and md5 checksums are provided; verify downloads with sha256.

4.2.1.2. Plain-text files

For simple checks, each of these returns a single version string (e.g., 5.0.11), with no trailing newline. Strip any surrounding whitespace before comparing.

URL

Contents

https://www.open-mpi.org/software/ompi/current/downloads/latest_release.txt

The latest release of the current (i.e., recommended) release series.

https://www.open-mpi.org/software/ompi/vA.B/downloads/latest_release.txt (e.g., https://www.open-mpi.org/software/ompi/v5.0/downloads/latest_release.txt)

The latest release in the vA.B release series (e.g., v5.0). Never reports a prerelease. Returns HTTP 404 if the series has no releases yet.

https://www.open-mpi.org/software/ompi/vA.B/downloads/latest_snapshot.txt (e.g., https://www.open-mpi.org/software/ompi/v6.0/downloads/latest_snapshot.txt)

The latest prerelease in the vA.B series (e.g., 6.0.0rc2) if the series currently has any prereleases; otherwise, the latest release in that series.

Each response carries a Last-Modified header set to the time of the release it reports.

Note

Despite its name, latest_snapshot.txt does not report nightly snapshot tarballs; the name is historical. Nightly snapshot tarballs have their own latest_snapshot.txt files (e.g., https://download.open-mpi.org/nightly/open-mpi/main/latest_snapshot.txt), which contain a snapshot version string as described in the version numbering section.

4.2.1.3. Atom feeds

For feed readers and chat or email integrations, Atom feeds are also available. Programs should use the JSON documents instead: the feeds are a subset of the same information, in a format meant for people’s feed readers.

Both feeds include prereleases. Each release series’ download page (e.g., https://www.open-mpi.org/software/ompi/v5.0/) also advertises both feeds for feed reader auto-discovery, so pasting that page’s URL into a feed reader works, too.

Each feed entry is one release (or prerelease):

  • <id>: a permanent identifier for the release, of the form tag:open-mpi.org,2026:openmpi/release/VERSION. It never changes.

  • <title>: Open MPI VERSION, with (prerelease) appended for prereleases.

  • <published> / <updated>: when the release was published.

  • <link rel="alternate">: the release series’ download page.

  • <link rel="enclosure">: one per downloadable file, with its URL, size (length), and file name (title). Atom has no standard place for checksums; get them from the download page or the JSON documents.

  • <category>: release or prerelease, and the series (e.g., v5.0).

4.2.1.4. Using these files

  • A version listed in these files is fully published: its files are downloadable and its web page is live.

  • To detect a new release, compare latest_release (of the index, or of the series you track) with the last version you saw. Do not compare version strings lexically (e.g., 5.0.10 is newer than 5.0.9); compare the numeric components, or simply check whether the version is in a list you have already seen.

  • The JSON documents and Atom feeds carry an ETag header and honor If-None-Match, so a poller can cheaply learn that nothing has changed (HTTP 304). Please poll no more often than every few hours; releases happen no more than a few times a month.

  • The per-series JSON documents and the Atom feeds return HTTP 503 (with a Retry-After header) rather than an incomplete document if the release details are temporarily unavailable; retry later.

  • schema_version changes only for incompatible changes. New fields may be added at any time without changing it, so ignore fields you do not recognize.

Caution

Do not use Git tags in the Open MPI GitHub repository to detect releases. A release is tagged before it is published, and, as noted above, GitHub.com-generated tarballs are not official Open MPI releases.