Release 6.22/00 - 2020-07-02


The all new PyROOT is now the default PyROOT! It’s a major upgrade, bringing much improved C++ support, and in generally more “pythonic” than the previous version. It’s based on cppyy which in turn is based on ROOT’s cling (and a bit more from ROOT). See also the PyROOT section in the release notes.

There is more major python news: ROOT can now be built against Python3 and Python2 at the same time, creating the necessary libraries for import ROOT to work from both python2 and python3, for a single ROOT build. Most of the binaries below now offer this.

RooFit has some nice improvements, such as workspace.Import(...) for Python, and myRooCategory["electron"] = 1 for Python and C++, and type-safe proxies. See the relevant release notes section for details.

TMVA has seen an extension of its Deep Learning module by adding support for LSTM and GRU Recurrent layers; all all recurrent layers (LSTM, GRU, and simple RNN) are now implemented for GPUs with the cuDNN library.

We have invested a lot of time in fixing many of the bugs that you found: thank you for these reports!

Release Notes

The release notes for this release can be found here.

Source distribution

Platform Files Size
source root_v6.22.00.source.tar.gz 165M

Binary distributions

Platform Files Size
CentOS 7 root_v6.22.00.Linux-centos7-x86_64-gcc4.8.tar.gz 185M
Fedora 30 root_v6.22.00.Linux-fedora30-x86_64-gcc9.3.tar.gz 225M
Fedora 31 root_v6.22.00.Linux-fedora31-x86_64-gcc9.3.tar.gz 225M
Fedora 32 root_v6.22.00.Linux-fedora32-x86_64-gcc10.1.tar.gz 227M
Ubuntu 16 root_v6.22.00.Linux-ubuntu16-x86_64-gcc5.4.tar.gz 200M
Ubuntu 18 root_v6.22.00.Linux-ubuntu18-x86_64-gcc7.5.tar.gz 218M
Ubuntu 19 root_v6.22.00.Linux-ubuntu19-x86_64-gcc9.2.tar.gz 223M
Ubuntu 20 root_v6.22.00.Linux-ubuntu20-x86_64-gcc9.3.tar.gz 224M
macOS 10.13 Xcode 10 root_v6.22.00.macosx64-10.13-clang100.pkg 315M
macOS 10.13 Xcode 10 root_v6.22.00.macosx64-10.13-clang100.tar.gz 200M
macOS 10.14 Xcode 10 root_v6.22.00.macosx64-10.14-clang100.pkg 314M
macOS 10.14 Xcode 10 root_v6.22.00.macosx64-10.14-clang100.tar.gz 200M
macOS 10.15 Xcode 11 root_v6.22.00.macosx64-10.15-clang110.pkg 314M
macOS 10.15 Xcode 11 root_v6.22.00.macosx64-10.15-clang110.tar.gz 200M

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 v6-22-00 v6-22-00


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).