FEFLOW 11 Release Notes
Introduction
Welcome to FEFLOW 11. In this document you will find information about new features, improvements and fixes, and what you need to know to install and get started with FEFLOW 11.
FEFLOW is a subsurface finite-element simulation system that provides best-in-class technology for modelling groundwater flow, contaminants, groundwater age, and heat transport. With its efficient user interface and its yet unmatched range of functionality, FEFLOW has been setting the standard in premium groundwater modelling for over 35 years.
As groundwater and subsurface modelling projects keep getting more demanding, so do the requirements on the capabilities of the modelling software. FEFLOW 11 provides several new key features that are described in the final section of this document.
System requirements
Supported Operating Systems
The supported operating systems listed below have been tested in accordance with MIKE’s Quality Assurance procedures. DHI’s warranty, as set out in the General Terms and Conditions (Schedule 1) for MIKE software and Software Maintenance Agreement (Schedule 4) only apply when MIKE software is installed and used on these supported systems:
- Windows: Win 10 Pro V22H2, Win 11 Pro V23H2 & V24H2, WinServ 2022 V21H2
- Linux Ubuntu: 22.04 LTS, 24.04 LTS
Any operating system not listed is considered unsupported. Installing or using MIKE software on an unsupported system is at Licensee’s own risk and DHI provides no warranty, no maintenance coverage, and is not obligated to offer support or troubleshooting.
Minimum hardware/software requirements
| Processor | Compatible with x64 instruction set architecture, 2.2 GHz or higher |
| Memory (RAM) | 16 GB or higher * |
| Storage | 64 GB or higher * |
| Display | Resolution 1920 x 1080 or higher |
| Graphics adapter | ≥ 2 GB memory, ≥ 24-bit colour, Shader version ≥ 1.30, minimum hardware accelerated OpenGL ≥ 2.0 / recommended hardware accelerated OpenGL ≥ 3.0 with fully supported Windows drivers ** |
| Software requirements |
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* The actual required amount of memory and disk space depends on the usage (application, model setup, size of data files, etc.).
** The (optional) PETSc solver can utilize the GPU on Nvidia® graphics cards with a compute capability of 7.0 or higher. Please note that some of these graphic cards have varying performance in single- compared to double-precision calculations. The GPU functionality is based on version 11.8 of the Nvidia® CUDA® Toolkit.
Installation
To install FEFLOW, please go to the 'windows' folder inside the 'FEFLOW' product folder and execute the 'start.exe' file from the downloaded, un-zipped installation files. Press the 'Install' button to invoke the installation dialog. In the dialog, please click on 'FEFLOW Program Files'. It is recommended to allow the set-up program to check for the latest patch on the MIKE Powered by DHI website.
The set-up program will automatically install all necessary files and folders onto your computer and make the appropriate modifications to the Windows Start menu.
Instructions on how to install and license FEFLOW 11 on a Linux system are provided in the FEFLOW 11 Online Help.
Licensing
With the 2026 Release, we have introduced a new licensing system for MIKE software.
For on-line users, the new Internet License Server is more secure and robust, and less dependent on a stable internet connection. This should significantly increase the overall reliability of the Internet License Server.
For off-line users, the main difference is that dongles and license files are replaced by a Network License Server that is locked to a specific computer. Just like the old dongles, a Network License Server can distribute licenses across a local network.
The existing Internet License Server will be phased out by the end of 2026. We will communicate more details of this phase-out to users of the existing system in Q2 2026.
In the new system,
- Every company needs an Administrator to manage Entitlements. This role will be created automatically by Customer Care.
- The Administrator can add Users in their company’s Webportal.
- The Administrator can set up Local License Servers for off-line usage.
- Users can configure their connection to the Internet License Server or a Local License Server from the new desktop DHI License Manager.
All the required files will be installed during the MIKE Software installation. The details of the installation, configuration and connecting to your License Server are described in the documentation for the DHI License Manager.
Starting FEFLOW
Double-click on the FEFLOW 11 icon on your desktop or launch FEFLOW via the Windows Start menu by selecting the program you would like to start. Typically, this will be 'FEFLOW 11 Standard' or the license-free 'FEFLOW 11 Viewer'.
FEFLOW can be used without a license after switching to Demo mode via Tools – License… in the main menu. This mode is indicated by the word 'DEMO' in the header of the FEFLOW application window and limits file loading and saving to models not exceeding five slices and 12500 nodes.
Support
For general support, please refer to our Customer Care Portal.
If you experience any difficulties, or if you have questions, please contact our Customer Care team at mike@dhigroup.com.
You can also contact your local Customer Care team for support in your local language. A list can be accessed here.
Known issues
No known issues at time of the FEFLOW 11 Update 4 (MIKE 2026.1) release.
Changelog
Below you can find a list of software changes in version 11 and subsequent update releases.
Looking for what’s new in FEFLOW 11? Discover the main features and usability improvements in the main release here.
FEFLOW 11 Update 4 (MIKE 2026.1)
Released June 24, 2026
New functionality
| Context | New feature |
Geologic modeling / 3D Supermesh / Python API |
The FEFLOW Python API has been extended by a number of methods for 3D-supermesh editing. |
Fixed issues
| Relevance | Description |
| High | For some meshes, starting a simulation after a problem-class change could result in a crash. |
| High | When creating a new well in the Well Manager not all parameters were initialized with a default value, which could cause a crash. |
| High | Setting up an open-loop geothermal system in a 2D model caused a crash. |
| High | Embedded Python scripts were not automatically executed when starting the simulation. |
| High | For unconfined or unsaturated models, saturation was not consistently applied as factor in the computation of the Total Stored Heat Content value in the Content Panel. |
| Medium | The Perform smoothing option in the Apply Elevation Points dialog of the 3D Slice/Layer Configuration could cause a crash. |
| Medium | Deleting the top slice of an unconfined model in the 3D Slice/Layer Configuration could cause a crash. |
| Medium | The 3D Slice/Layer Configuration did not consistently honor the bottom slice as fixed when applying a minimum slice distance. |
| Medium | In some situations, calling the OnUpdateMaterial() API function could result in a deadlock of the application. |
| Medium | The import of well groups failed in some cases. |
| Medium | The content history chart for energy indicated volumetric instead of energy units. |
| Medium | When applied to an unstructured (tetrahedral) mesh, the In/Outflow on top/bottom parameter was incorrectly presumed to specify a flux perpendicular to the local surface/bottom rather than in strictly vertical direction. |
| Medium | Editing physical-property values in the Borehole Heat Exchanger Dataset Editor dialog resulted in erroneous unit conversion. |
| Low | Changing the rate-budget units was not immediately reflected in the GUI. |
| Low | Some mesh-editing tools were shown/enabled even when not applicable to the current mesh. |
| Low | In simulation charts for wells, the label "Average" has been replaced by the more accurate "Injection/Extraction". |
| Low | Using the FEM mesh import from maps option in the new-model wizard resulted in a crash. |
| Low | Some edit fields were showing "nan" instead of being empty. |
FEFLOW 11 Update 3
Released April 30, 2026
Fixed issues
| Relevance | Description |
| High | An incorrect heat budget was computed for open-loop systems that were set up using the well manager. |
| High | Applying flow-well and transport point-source boundary conditions at the same node could result in a crash. |
| High | In some cases, opening a .dac simulation record resulted in a crash for models containing discrete-feature elements. |
| Medium | The Structural Model Editor did not prevent conceptually invalid combinations of adjacent horizon classes. |
| Medium | When creating a 3D unstructured finite-element mesh with the TetGen mesh generator, no initial node/edge/face selections reflecting the features given in a .smh3d supermesh were provided. |
| Medium | The Edge Size parameter in the From Supermesh Elements section of the Meshing panel was only applied if set to value less than 1.0. |
| Low | Multiple items could be selected in the Structural Model Editor but an edited value was only applied to the last one. |
| Low | Unselecting items in the Structural Model Editor only worked after first selecting all items. |
| Low | The deprecated ".smh" legacy supermesh format was still offered as an option in the Save as... dialog. |
FEFLOW 11 Update 2
Released March 27, 2026
Fixed issues
| Relevance | Description |
| High | License installation failed for user names containing non-ASCII characters. |
| High | Darcy velocity was incorrectly shown and reported via API for flow-only models, i.e., models including neither heat nor mass transport. |
| High | Open-loop geothermal systems, once defined, were incompatible with subsequent changes to the finite-element mesh topology. |
| High | Repeatedly recreating the FE mesh could lead to crash. |
| High | The initial hydraulic-head value at a multilayer-well node was set to zero when switching the problem class. |
| Medium | Entering Demonstration ("Demo") mode failed when launching FEFLOW without a license. |
| Medium | Changing properties of view-overlay items such as legends could in some circumstances cause a crash. |
| Medium | During usage, some text-input fields in the graphical user interface could appear black. |
| Medium | Polyline conversion from a map to 3D Supermesh elements was incorrect when selecting Grouping | By Name. |
| Low | When displaying a multilayer well in a view window, the respective symbol was not always shown on all slices. |
FEFLOW 11 Update 1
Released March 3, 2026
Fixed issues
| Relevance | Description |
| High | Attempting to access a license while none was available could result in a crash. |
| High | Incorrect results were obtained for steady-state simulations of 3D problems with transfer boundary conditions. |
| High | Inserting slices into a model containing any bore-hole heat exchanger could result in a crash. |
| High | Built with version 6.10.1 of the third-party Qt GUI toolkit, FEFLOW 11 was found to slow down in cases of prolonged single-session use. FEFLOW 11 Update 1 is built with Qt long-term support version 6.8.3, which prevents the issue. |
| Medium | The geomodeling module supplied by Geode-Solutions has been updated to version 7.1.6 that provides improved mesh quality and more comprehensive error handling. |
| Medium | To resolve pinching in the Meshing-panel workflow, the Unstructured-Pinching dialog was shown only, instead of first offering multiple options via the Layer Resolution dialog. |
| Medium | Cloning a cross-section view containing any multilayer well or bore-hole heat exchanger could result in a crash. |
| Medium | In some cases the loading of models that had the time-axis display set to Calendar Date/Time could fail with a crash. |
| Medium | When importing nodal concentration values into a multispecies model, only the first species was targeted. |
| Low | User-assigned view-window names were not saved to file and thus not persistent. |
| Low | When displaying error-bars, the colors green and red for filling the bar inside/outside the confidence interval were reversed. |
| Low | The Material regions legend remained visible in the view window despite the Material regions item in the View Components tree having been unselected. |
FEFLOW 11 (MIKE 2026)
Released January 29, 2026
New functionality
| Context | New feature |
Geologic modeling / 3D Supermesh |
The new Structural Model Editor enables you to build geological models using the FEFLOW graphical user interface. With the editor, you can compile borehole data, fault networks, and stratigraphic sequences, and use them to create a proper modelling domain in the Supermesh projects that are ready to be discretized into finite elements. |
Geologic modeling / 3D Supermesh |
The Supermesh Preprocessing panel equips you with a new set of Geometric Tools to correct 3D external datasets that are intended as input for a 3D Supermesh. These tools are powered by Geode-Solutions and allow to reset topology, individualize components, compute intersection, remove outer components, remove components below certain size threshold, and more. The tools can be applied selectively you to improve the quality of specific geometric features at any step of the 3D Supermesh preparation. |
Geologic modeling / 3D Supermesh / Python API |
FEFLOW 11 provides full support of the Geometric Tools by the new processSupermesh method of the 3D Supermesh document. |
3D Supermesh / Meshing |
FEFLOW 11 introduces a new Layered-mesh generator powered by Geode-Solutions for the 3D Supermesh interface. The new mesh generator is intended for projects where the model geometry is suited for by a 2.5 D representation (continuous layers). |
Geologic modeling / Pinched-out layers |
FEFLOW 11 supports layers that do not extend over the full horizontal domain, i.e., that pinch out within the model. These layers can be fully accessed via the 2D Slice view windows. Layer pinch-out can be achieved via the newly enhanced 3D Slice/Layer Configuration dialog, or with the new interactive Fuse-delete tool that enables removal of selected elements and automatically closes the gap by connecting the elements below to the ones above. |
Geologic modeling / Layered meshes |
The new Split Layer tool allows to locally increase the vertical resolution by splitting a selected (possibly pinched) layer into multiple layers. |
Geothermal modeling / Well Manager |
The Well Manager dialog now includes a dedicated Open Loop System section that supports detailed description of geothermal systems. Here, you can define well groups, specify heat demand by temperature difference or power, and configure system parameters. |
Geothermal modelling / Result reporting |
The Observation Data dialog has been extended with a Geothermal section to organize all modelling results related to geothermal closed-loop systems (BHE) and open-loop systems. This enhancement provides higher flexibility for comparing modelled vs. simulated values and control of user-defined chart settings. |
Geothermal modelling / Charts |
FEFLOW 11 introduces multiple new charts that specifically support geothermal applications: BHE Heat Rate, Open-Loop Heat Rate, Open-Loop Flow Rate, Open-Loop Temperature Difference and Open-Loop Inlet/Outlet Temperature. |
Well Manager |
Workflows in the Well Manager have been improved. The Well Group creation is now independent of a preliminary well definition. This allows you to define and create the groups and their corresponding settings a priori. Subsequently, groups can be assigned to wells on demand. |
Well Manager / Interactive assignment |
The Editor toolbar (commonly used for the assignment) has been extended to support the interactive assignment of well groups. By using existing selection tools, you can now group BHEs, MLWs and Well BCs in Slice and 3D view windows. |
Computational performance |
Efficiency improvements to the numerical engine and to the treatment of constrained boundary conditions make FEFLOW 11 faster than earlier versions. |
Visualization |
Cross-sectional views can now display boundary conditions and observation points. This enhancement improves model interpretation and presentation by showing key elements such as wells in the local context. |
Python Usage |
FEFLOW 11 includes a full-featured scripting editor and Python console as part of the graphical user interface. Without leaving the FEFLOW GUI, you can write, format, and run scripts, customize the environment, install packages, and encrypt scripts for added security. |
Python API |
To streamline the integration of sparse data into FEFLOW models, the Python API has been extended by new regionalization methods that enable direct interpolation of external datasets. You can use them to efficiently assign elemental and nodal parameters, such as material properties or boundary conditions, with custom interpolators. |
Licensing and SMA-Benefits |
With FEFLOW 11, the FEFLOW Advanced Features package introduces Python, Geomodelling and Geothermal modules. The package gives unlimited access to new specific and advanced software developments through the duration of the subscription period or the duration of the service maintenance (SMA) period. |
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