# OpenGeoSys 6.5.8 released!

**URL:** <https://discourse.opengeosys.org/t/opengeosys-6-5-8-released/1855>\
**Category:** Announcements\
**Created:** [May 27, 2026, 9:56am UTC](https://discourse.opengeosys.org/t/opengeosys-6-5-8-released/1855 "2026-05-27T09:56:56Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![bilke](https://discourse.opengeosys.org/user_avatar/discourse.opengeosys.org/bilke/32/868_2.png) [@bilke](https://discourse.opengeosys.org/u/bilke)\
**Post date:** [May 27, 2026, 9:56am UTC](https://discourse.opengeosys.org/t/opengeosys-6-5-8-released/1855/1 "2026-05-27T09:56:56Z")

</div>

[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.20269146.svg)](https://doi.org/10.5281/zenodo.20269146)

We are happy to announce the release of **OpenGeoSys 6.5.8**!

## Links

- [Release page on www.opengeosys.org](https://www.opengeosys.org/stable/releases/6.5.8/)
- [GitLab Release](https://gitlab.opengeosys.org/ogs/ogs/-/releases/6.5.8)
- [Zenodo Release](https://zenodo.org/record/20269146)
- [PyPI Release](https://pypi.org/project/ogs/6.5.8/)
- Also available on [Conda](https://anaconda.org/channels/conda-forge/packages/ogs/overview) and [Guix](https://hpc.guix.info/package/ogs-serial)

## Process’ changes

### Component transport process / reactive transport process with coupling of Phreeqc

- [!5548](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5548) The data exchange between PhreeqC and OGS is now using string in the memory as the default option. It should accelerate the simulation for models with large domains.
- [!5591](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5591) This MR makes OGS-PhreeqC reactive transport simulations to run in either or both OpenMP and MPI environment (hybrid parallelization).

### HeatTransportBHE

- [!5544](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5544) The BHEs flow and temperature control now requires parameters as input. The possible types are simplified to InflowTemperature, Power, BuildingPower and AdvancedBuildingPower.
- [!5571](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5571) The BHE now can be defined with changing diameter over depth. The flow velocity and thermal resistance calculation will be changed accordingly during the simulation.

### HT

- [!5693](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5693) Refactor HT documentation; update monolithic scheme

### ThermoHydroMechanics

- [!5628](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5628) Add mass balance equation type.
- [!5635](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5635) Add `sigma_ice` and `ice_volume_fraction` ip/avg data output.
- [!5617](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5617) Extract `EquationBalanceType` from `LiquidFlow` and optimize local monolithic assembly.
- [!5625](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5625) Optimize the computation of the contribution of strain coupling to the RHS.

### ThermoRichardsMechanics

- [!5574](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5574) Separate data and model structs of constitutive models into individual files.

## Constitutive relations (material models)

- [!5531](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5531) Adds the temperature dependent Lu-Mc Cartney WRC.
- [!5695](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5695) Support for ranges start:end in media ids

## Numerics

- [!5694](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5694) Refactor NonlinearSolver to support multiple solver strategies

## Generic features

- [!5602](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5602) Enables multiple OGS simulations to be started inside the same Python process (but there can be only a single MPI/PETSc OGS simulation in a single Python process).

## Tools

- [!5609](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5609) Add boundary mesh extraction to generateStructuredMesh.
- [!5631](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5631) Relative tolerance algorithm for search of collapsible nodes.

## Python & Jupyter

- [!5682](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5682) Benchmarks notebooks run now with OGSTools 0.8.1. Now, additionally Python 3.14 is supported.
- [!5632](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5632) Relax embedded Python venv site-packages validation

## Testing

- [!5598](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5598) Add coverage option to testrunner.
- [!5605](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5605) Speedup code coverage and include more tests.
- [!5633](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5633) Add PETSc coverage job.

## Bug fixes

[!5606](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5606) re-enables Jacobian comparisons for processes that use the OpenMP parallelized assembly code. Nevertheless, the compare Jacobian feature is restricted to a single assembly thread to avoid concurrent file write accesses.

## CMake

- [!5642](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5642) Clang (-tidy) preset.
- [!5644](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5644) Refactored check headers, use `FILE_SET`.
- [!5570](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5570) Feature matrix generation integration in build process.
- [!5580](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5580) Build time header checks.

## Infrastructure

- [!5652](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5652) Adding xdmfdiff to eve PETSc container.
- [!5655](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5655) Hugo build-dir based.
- [!5656](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5656) Updated devcontainer config and docs.
- [!5658](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5658) Refactored publications.

## File I/O

- [!5471](https://gitlab.opengeosys.org/ogs/ogs/-/merge_requests/5471) Re-implement FEFLOWGeoInterface with libxml2.

## Version info

- LIS: 2.0.30
- OGSTools: 0.8.1