Release 6.24/00 - 2021-04-15


LLVM used by ROOT has been updated to LLVM 9, which brings full C++17 support. I/O and, as a consequence, RDataFrame operations have been accelerated especially for use in multi-threaded environments.

Speaking about RDataFrame, several new features made it into v6.24, especially noteworthy are ROOT::RDF::RunGraphs and the support for “indexed friends”. An experimental preview of ROOT’s upcoming succession to PROOF, ROOT.RDF.Experimental.Distributed, is included in ROOT v6.24/00. It is used just like RDataFrame and can run the analysis on a cluster. Currently, running locally and on a Spark cluster are implemented; support for Dask is on its way.

ROOT now offers a new portable random number generator with fantastic properties: RANLUX++. TMVA adds an interface to PyTorch, to make your TMVA tools also available for this backend, as a more flexible alternative to the PyKeras interface.

RooFit comes with speed improvements and additional robustness (RooStats::HypoTestInverter). The main speed-up is due to RooFit’s new, architecture-specific compute libraries: those are automatically selected for the CPU currently in use, and accelerate BatchMode computations by up to 4x. Together with the RooFit acceleration since v6.20, typical RooFit analyses will now see speed-ups of 4x..16x. And a long-standing and highly relevant issue was fixed: binned fits are now unbiased. If you were using RooDSCBShape or RooSDSCBShape: please switch to RooFit’s superior version, RooCrystalBall, which replaces these two.

ROOT now supports WLCG Bearer Tokens through Davix, so allow you to use “the grid’s” modern authentication mechanism. ROOT now supports building against Xrootd 5 client libraries.

In other news, ROOTJS saw a major upgrade; the reference guide now allows to switch ROOT versions for a given class; and building ROOT now defaults to your compiler’s default C++ standard.

And of course also this version has a long list of fixed issues, as shown in the release notes.

Release Notes

The release notes for this release can be found here.

Source distribution

Platform Files Size
source root_v6.24.00.source.tar.gz 177M

Binary distributions

Platform Files Size
CentOS 7 root_v6.24.00.Linux-centos7-x86_64-gcc4.8.tar.gz 183M
Fedora 30 root_v6.24.00.Linux-fedora30-x86_64-gcc9.3.tar.gz 219M
Fedora 31 root_v6.24.00.Linux-fedora31-x86_64-gcc9.3.tar.gz 220M
Fedora 32 root_v6.24.00.Linux-fedora32-x86_64-gcc10.2.tar.gz 224M
Ubuntu 16 root_v6.24.00.Linux-ubuntu16-x86_64-gcc5.4.tar.gz 196M
Ubuntu 18 root_v6.24.00.Linux-ubuntu18-x86_64-gcc7.5.tar.gz 214M
Ubuntu 19 root_v6.24.00.Linux-ubuntu19-x86_64-gcc9.2.tar.gz 215M
Ubuntu 20 root_v6.24.00.Linux-ubuntu20-x86_64-gcc9.3.tar.gz 216M
macOS 10.14 x86_64 Xcode 11 root_v6.24.00.macos-10.14-x86_64-clang110.pkg 327M
macOS 10.14 x86_64 Xcode 11 root_v6.24.00.macos-10.14-x86_64-clang110.tar.gz 210M
macOS 10.15 x86_64 Xcode 12 root_v6.24.00.macos-10.15-x86_64-clang120.pkg 321M
macOS 10.15 x86_64 Xcode 12 root_v6.24.00.macos-10.15-x86_64-clang120.tar.gz 207M
macOS 11.2 arm64 Xcode 12 root_v6.24.00.macos-11.2-arm64-clang120.pkg 307M
macOS 11.2 arm64 Xcode 12 root_v6.24.00.macos-11.2-arm64-clang120.tar.gz 196M
macOS 11.2 x86_64 Xcode 12 root_v6.24.00.macos-11.2-x86_64-clang120.pkg 321M
macOS 11.2 x86_64 Xcode 12 root_v6.24.00.macos-11.2-x86_64-clang120.tar.gz 207M
Windows Visual Studio 2019 (debug) root_v6.24.00.win32.vc16.debug.exe 160M
Windows Visual Studio 2019 (debug) 235M
Windows Visual Studio 2019 root_v6.24.00.win32.vc16.exe 86M
Windows Visual Studio 2019 116M

Installations in CVMFS

Standalone installations with minimal external dependencies are available at:


Example for setting up ROOT from CVMFS

. /cvmfs/


The entire ROOT source can be obtained from our public Git repository:

git clone

The release specific tag can be obtained using:

cd root
git checkout -b v6-24-00 v6-24-00


Windows 10/7/… are supported. We offer two packaging types:

  • exe: a regular Windows installer package also setting up the required environment variables. With uninstall via “Control Panel” / “Add or Remove Programs”. Simply download and start. You can double-click ROOT to run it; ROOT files get registered with Windows.
  • tar: unpack e.g. with 7zip. Start ROOT in a Microsoft Visual Studio Prompt (in Start / Programs / Microsoft Visual Studio / Tools). If you installed ROOT to C:\root then call C:\root\bin\thisroot.bat before using ROOT to set up required environment variables.

Important installation notes

  • You must download the binary built with the exact same version of Visual Studio than the one installed on your system.
  • Do not untar in a directory with a name containing blank characters.
  • Take the release version if performance matters.
  • If you want to debug your code you need the ROOT debug build (you cannot mix release / debug builds due to a Microsoft restriction).