Hi GROMACS users,
Thanks to all of you who tested the GROMACS 2026 beta release! Thanks to you, we improved a couple of things on the beta release and are proud to announce the first release candidate of GROMACS 2026!
We are making this available to you to get an early taste of GROMACS 2026, and most importantly to get feedback from you about how well things work. While we try our hardest to keep the quality of GROMACS as high as possible, we’re human, we overlook things and we need your many pairs of eyes to help to build a tool that we can all use to do good science! We really need you to test your kinds of simulation on your hardware, both for correctness and performance. This is particularly important if you are using “interesting” hardware or compilers because we can’t test all of them!
Please do not use this version for doing science you plan to publish - it needs more testing before it’s reliable enough for that. Similarly, please don’t use this version as a base for a project that bundles or forks GROMACS.
What new things can you expect? (See the release notes for more details.)
- Two protein force fields from AMBER, ff14SB and ff19SB, have been ported to GROMACS as AMBER14SB and AMBER19SB. The ports also include the new OPC and OPC3 water models as well as several others.
- Expanded support for running simulations with Neural Network Potential models, now including link atom treatment for NNP/MM, pairlist input, and electrostatic embedding models.
- Experimental support for H5MD as a trajectory output format for
mdrun.
Check the installation guide, user guide, and reference manual for the details.
Your testing helps us to harden the final release. To follow progress and give further feedback, have a look at the 2026 milestone on gitlab and report issues there.
If all goes to plan, we hope to ship the final 2026 release in January, but that relies on people joining in and helping us to test! We hope you will consider making that contribution, so that we can continue to deliver high-quality free simulation software that will be useful to you.
You can find the code, manual, release notes, installation instructions and test suite at the links below.
Code: https://ftp.gromacs.org/gromacs/gromacs-2026-rc.tar.gz
Documentation: GROMACS 2026-rc documentation
(includes install guide, user guide, reference manual)
Release Notes:
Test Suite:
https://ftp.gromacs.org/regressiontests/regressiontests-2026-rc.tar.gz
Happy testing!
Lukas