Introduction to HTCondor Versions
This chapter provides descriptions of what features have been added or bugs fixed for each version of HTCondor. The first section describes the HTCondor version numbering scheme, what the numbers mean, and what the different releases are. The rest of the sections each describe the specific releases.
HTCondor Version Number Scheme
We changed the version numbering scheme after the 9.1.3 release: what would have been the next 9.1.x release is now the 9.2.0 release. We made this change to give us additional flexibility in releasing small updates to address specific issues without disturbing the normal development of HTCondor. The version number will still retain the MAJOR.MINOR.PATCH form with slightly different meanings. We have borrowed ideas from Semantic Versioning.
The MAJOR number increments with each new Long Term Support (LTS) release. A new LTS release may have backward-incompatible changes and may require updates to configuration files. If the current LTS version is 23.0.12, the next one will be 24.0.1. A new LTS release is expected in the third quarter of each year. The LTS major version number matches the year of initial release.
The MINOR number increments each feature release. This number stays constant for LTS releases. If the current feature version is 23.2.3, the next one will be 23.3.0. A new feature release is expected every month.
The PATCH number increments when we have targeted fixes. For the LTS releases, a patch release is expected every month and may occur more frequently if a serious problem is discovered. For new feature releases, the number of patch releases depends on number of problems that are resolved during testing.
Types of Releases
A new LTS release is numbered X.0.1. When the new LTS version is released, the X-1 feature versions transition to LTS versions (bug fixes only). This LTS release will be supported for approximately two years. The previous LTS release and newly minted LTS release from the latest feature release are supported for approximately one year after a new LTS version is released. The final feature release undergoes a stabilization effort where the software is run through multiple code quality tools (such as Valgrind) to assure the best possible LTS release. The MAJOR.0.1 version is not released until the stabilization effort is complete.
An LTS patch release is numbered X.0.Y, and is an update to the LTS major release. The patches are reviewed to ensure correctness and compatibility with the LTS release. These releases contain bug fixes and security updates and are released when a major issue is identified, or just before the next feature release. These releases go through our entire testing process. Large code changes are not permitted in the LTS release. Enhancements are not implemented in the LTS release unless there is minimal impact with a major benefit. Ports to new platforms will appear in the LTS release. The HTCondor team guarantees that patches to the LTS release are compatible. Paid support contracts are only available for the LTS releases.
A feature release is numbered X.Y.Z and includes one or more new features. The software goes through our entire testing process. We use these releases in production at the Center for High Throughput Computing (CHTC) and Open Science Pool (OSPool). These releases contain all the patches from the LTS release.
The HTCondor development team guarantees protocol compatibility between the feature release and the LTS releases. However, changes in behavior may be observed, and adjustments to configuration may be required when new features are implemented.
By default, each MAJOR version is compatible with adjacent MAJOR versions. That is, versions X.y.z will be compatible with X-1.y.z and X+1.y.z versions, such that nodes in a cluster may be upgraded without losing state information. There may be a pause in operation during upgrade. Check the release notes for exceptions prior to updating nodes.
Support Life Cycle
We plan to release a new LTS version every August. The support life cycles are directly related to the release dates.
Version |
Release Date |
End of Support |
|---|---|---|
25.x |
September 29, 2025 |
August 2027 |
25.0 LTS |
September 29, 2025 |
August 2027 |
24.x LTS |
October 31, 2024 |
August 2026 |
24.0 LTS |
October 31, 2024 |
August 2026 |
Repositories
These LTS and feature versions are each served out of four repositories.
The
snapshotrepository contains a snapshot of our most recent builds. These builds pass all of our unit tests. However, they have not gone through any integration testing.The
alpharepository contains builds that we are testing in CHTC. These builds may be unstable as we find issues with new release candidates.The
betarepository contains builds that have passed integration tests on our production CHTC pool and are made available for testing on the wider Open Science Pool (OSPool).The
releaserepository contains final releases that have passed testing on the OSPool.
Recommendations
If you are new to HTCondor or require maximum stability in your environment, use an LTS release. Updates to the latest LTS release should be seamless. A new LTS release will appear about every twelve months with clear directions on issues to address when upgrading to the new LTS release.
If you want to take advantage of the latest features, use the feature releases. This is an opportunity see our development directions early, and have some influence on the features being implemented. It is what we use in our production environment.