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ROOT

ANALYTICS
Velocity5.0

Data analysis framework for large scale scientific data processing

root.cern ↗

ROOT 6.40 LTS patches CMake 4.4 compatibility and 25+ tracked issues in one drop.

hepscientific-computingdata-analysiscerncpp
◆Current state
ROOT 6.40 LTS is in active patch maintenance. The 6.40.04 update fixed a CMake 4.4 compatibility break that was blocking new builds, alongside 25+ tracked issues spanning NTuple late-extension bugs, RooFit integral correctness, GDML geometry parsing, and Minuit2 robustness. Multiple older series — 6.36, 6.32, 6.30, 6.28 — continue receiving minor patches, reflecting the long support windows typical of HEP infrastructure software.
◆Where it's heading
The 6.40 LTS capabilities — concurrent histogram filling, RDataLoader, S3/libcurl-backed I/O, experimental opt-out of auto-registration — shipped in 6.40.00 and the patch cycle is now focused on correctness and compatibility. ROOT 7's full-API future continues to be a long-horizon goal; in the near term, the project is consolidating the 6.40 LTS base.
◆Prediction
Expect continued 6.40.x patches at this cadence, with occasional older-series backports. A 6.42 development series will eventually surface new capabilities, but there is no visible signal of its timeline from the current patch activity.

◆Recent moves

  1. 15d ago

    ROOT 6.36.14: minor patch for STS series

    A minor patch for the 6.36 series with details linked externally. The 6.36 line is a short-term support series now superseded by 6.40 LTS; continued patches here serve users who haven't migrated yet.

    View source ↗
  2. 20d ago

    v6-40-04

    The 6.40.04 patch addresses 25+ tracked issues across the LTS series, most notably a CMake 4.4 configuration failure that was blocking builds on newer toolchains. Substantive correctness fixes land in RooFit (RooBinIntegrator, ExtendPdf range fits), NTuple (double-free on RVec resize, wrong type name in streamer fields), and Minuit2 (Hessian robustness). This is a meaningful patch with real impact on analysis correctness, not just infrastructure tidying.

    View source ↗
  3. 3mo ago

    ROOT 6.32.24: minor patch for STS series

    Minor fixes for the 6.32 STS series, details at the release notes link. A legacy maintenance drop for users on an older supported branch.

    View source ↗
  4. 3mo ago

    ROOT 6.30.12: minor patch for STS series

    Minor fixes for the 6.30 STS series. A legacy maintenance drop for users on an older supported branch.

    View source ↗
  5. 3mo ago

    ROOT 6.28.16: minor patch for STS series

    Minor fixes for the 6.28 STS series. A legacy maintenance drop for users on an older supported branch.

    View source ↗
  6. 3mo ago

    v6-38-06

    The final patch of the 6.38 short-term support series, explicitly noting its supersession by 6.40 LTS. The release addressed 20+ items including TFile UUID uniqueness, memory leaks in TFile::Open, PyROOT GIL issues, web canvas format handling, and RDataFrame distributed execution bugs. A substantive cleanup that closes out the 6.38 branch responsibly.

    View source ↗