ROOT Version 6.40 Release Notes

2026-5

Introduction

For more information, see:

http://root.cern

The following people have contributed to this new version:

Bertrand Bellenot, CERN/EP-SFT,
Jakob Blomer, CERN/EP-SFT,
Lukas Breitwieser, CERN/EP-SFT,
Philippe Canal, FNAL,
Olivier Couet, CERN/EP-SFT,
Marta Czurylo, CERN/EP-SFT,
Florine de Geus, CERN/EP-SFT and University of Twente,
Jonas Hahnfeld, CERN/EP-SFT and Goethe University Frankfurt,
Fernando Hueso Gonzalez, IFIC (CSIC-University of Valencia),
Stephan Hageboeck, CERN/EP-SFT,
Aaron Jomy, CERN/EP-SFT,
Sergey Linev, GSI Darmstadt,
Lorenzo Moneta, CERN/EP-SFT,
Vincenzo Eduardo Padulano, CERN/EP-SFT,
Giacomo Parolini, CERN/EP-SFT,
Danilo Piparo, CERN/EP-SFT,
Jonas Rembser, CERN/EP-SFT,
Silia Taider, CERN/EP-SFT,
Devajith Valaparambil Sreeramaswamy, CERN/EP-SFT,
Vassil Vassilev, Princeton,

Deprecation and Removal

Build System

Core Libraries

I/O

TTree

RNTuple

Math

RooFit

RDataFrame

Python Interface

Command-line utilities

JavaScript ROOT

Experimental features

Versions of built-in packages

Items addressed for this release