GROMACS 2026.3 release notes

This version was released on June 25th, 2026. These release notes document the changes that have taken place in GROMACS since the previous 2026.2 version, to fix known issues. It also incorporates all fixes made in version 2025.4 and earlier, which you can find described in the Release notes.

Fixes where mdrun could behave incorrectly

Avoid deadlock with NVSHMEM and GMX_DISABLE_STAGED_GPU_TO_CPU_PMEPP_COMM

Previously, GROMACS would freeze early on with this combination of enabled features.

Issue 5637

Fixes for gmx tools

Fix position restraint reference with pbc=xy and ref-coord-scaling=com

With pbc=xy and ref-coord-scaling=com, gmx grompp would incorrectly subtract the COM of the restraint group from the z-component of the reference coordinates. This should in most cases have caused obvious errors.

Issue 5630

Prevent buffer overflow in gmx angle

Previously, if gmx angle was used to measure a dihedral, an internal loop would execute exactly three times, regardless of how many angles were provided. If fewer than three angles were provided, this led to a heap buffer overflow.

Issue 5620

Fix gmx anaeig -over when number of eigenvectors differs

Previously, gmx anaeig -over -v ev1.trr -v2 ev2.trr -first 1 -last 1 would exit with a fatal error if the two eigenvector files contained a different number of eigenvectors. Computing the subspace overlap of a set of eigenvectors should only require the two eigenvector files to have the same number of atoms, not the same number of stored eigenvectors.

See also this discussion thread

Fixes that affect portability

Fixed compilation error with Visual Studio and CUDA 13

Fixed compilation error with HeFFTe and NVHPC compiler

Fixed gmxapi build failures with CUDA

In some configurations, building gmxapi could have failed with The link interface of target "Gromacs::libgromacs" contains: OpenMP::OpenMP_CUDA but the target was not found.

Issue 5656

Miscellaneous

Update documentation and warnings in gmx angle

Previously, the documentation and warning messages did not specify specific requirements to generate certain optional output files. Another warning message suggests the user uses an option from the legacy version of the tool. Documentation, warnings, and errors were updated for clarity.

Issue 5625