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COMSOL® SOFTWARE VERSION 6.4 UPDATE 2

Released March 19, 2026

Update 2 to the COMSOL® software version 6.4 (build 6.4.0.378) provides performance and stability improvements to COMSOL Multiphysics®, COMSOL Server™, COMSOL Client for use with COMSOL Server™, and Model Manager server.

The update applies to COMSOL® software version 6.4 (builds 6.4.0.293 and 6.4.0.343).

If you have version 6.4 and a valid license with a current subscription, you can apply update 2 by performing a full installation of version 6.4 from the Product Download page, which will include all updates.

Terms and Conditions

This update is governed by the COMSOL Software License Agreement that is displayed upon installation of COMSOL Multiphysics® or by the terms and conditions of any other agreement COMSOL may have with your organization. For the latest version of the COMSOL Software License Agreement, including any provisions applicable to this update, see the License Agreements page. By downloading and using this update, you agree to use this update in accordance with the current version of the COMSOL Software License Agreement or with the terms and conditions of any other agreement we may have with your organization.

Note: Updates 1 and 2 to version 6.4 of the COMSOL® software do not introduce any changes to the COMSOL Software License Agreement.

How to Apply the Software Update

Before proceeding with your installation, make sure that you close and exit any running COMSOL® processes and any software you have running that correlates to a LiveLink™ product you would like to update (Excel®, MATLAB®, Simulink®, or a CAD software program).

Updating COMSOL Multiphysics®

The easiest way to install the update for COMSOL Multiphysics® is to start the program and then select Check for Product Updates. If using the Windows® operating system, this option is located in the File menu under Help. If using the Linux® operating system or macOS, this option is located in the Help menu.

For more information on how to install the update and for offline installation instructions, see the Additional Instructions tab below.

To check that the update installation was successful, first start the COMSOL Multiphysics® software and then select the About COMSOL Multiphysics menu option. If using the Windows® operating system, this option is located in the File menu under Help. If using the Linux® operating system or macOS, this option is located in the Help menu. The listed version should be COMSOL Multiphysics® 6.4 (build 6.4.0.378).

Updating COMSOL Server™

To update COMSOL Server™ for the Windows® operating system, run the Update program from the COMSOL Launchers folder in the Start menu. Note that the COMSOL Server™ service process needs to be stopped before applying the update.

For more information on how to install the update, installing on other operating systems, and offline installation, see the Additional Instructions tab below.

To check that the installation was successful, first make sure that COMSOL Server™ is running; then, navigate to COMSOL Server™ in a web browser and follow the About COMSOL Server™ link in the lower-right corner. The new version should be COMSOL Server™ 6.4 (build 6.4.0.378).

Updating COMSOL Client for Use with COMSOL Server™

To update COMSOL Client for the Windows® operating system, download the new version from Client Download and install. The previous 6.4 installation will be overwritten. In order to run properly, your installation of COMSOL Client must have the same version number as the COMSOL Server™ installation that you connect to.

Updating the Model Manager Server

To update Model Manager server for the Windows® operating system, run the Update program from the COMSOL Launchers folder in the Start menu. Note that the Model Manager server process needs to be stopped before applying the update.

For information on how to install the update, see the Additional Instructions tab below.

To check that the installation was successful, first make sure that Model Manager server is running; then, navigate to the Model Manager server in a web browser and follow the About link at the bottom of the page. The new version should be COMSOL Model Manager server 6.4 (build: 6.4.0.378).

The following instructions apply only if you are not using the method based on the Check for Product Updates menu item, as described above.

Updating COMSOL Multiphysics®

1

Check the Version Number

  1. Start COMSOL Multiphysics®.
  2. Open the About COMSOL Multiphysics dialog box. If using the Windows® operating system, the dialog box can be found in the File menu under Help. If using either the Linux® operating system or macOS, the dialog box can be found under the Help menu.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Install the Update

Before you proceed with the installation, make sure to exit any running COMSOL Multiphysics® processes or any software you have running that correlates to a LiveLink™ product you would like to update (Excel®, PowerPoint®, MATLAB®, or a CAD software).

  1. Start the COMSOL® software update installer:
    • Windows® operating systems: Run the Update program from the COMSOL Launchers folder in the Start menu, or directly from the COMSOL 6.4 installation folder. The COMSOL Launchers folder can be found in the installation folder, for example, C:\Program Files\COMSOL\COMSOL64\Multiphysics\COMSOL Launchers.
    • Linux® operating systems: Run the update script from the COMSOL 6.4 installation directory, for example, /usr/local/comsol64/multiphysics.
    • macOS: Run the COMSOL Update application from the COMSOL 6.4 installation directory, for example, /Applications/COMSOL64/Multiphysics.
  2. The next step will be taken in the installer program's Options page and depends on whether or not you have a live internet connection or if you plan to download the update file for offline installation:
    • If you have an internet connection: Keep the Direct download setting.
    • If you have an internet connection via a proxy server: Select Download via proxy server and enter your proxy configuration settings.
    • If you do not have an internet connection on the target computer or if you want to apply the update several times on multiple computers: Download the following file to a folder on your computer
      DOWNLOAD UPDATE (6.5 GB)
      In the installer program, select Manual download and click Browse. Navigate to the downloaded file and click Open.
  3. Click Next to get to the Release Notes page for reviewing the update details.
  4. Click Next to get to the Install page and review the software components affected by the update.
  5. In the Install page, click Install to start the installation of the update.
3

Check the Installation

  1. Start COMSOL Multiphysics®.
  2. Open the About COMSOL Multiphysics dialog box. If using the Windows® operating system, this is located in the File menu under Help. If using the Linux® operating system or macOS, this is located in the Help menu.
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)

Updating COMSOL Server™

1

Check the Version Number

  1. Navigate to the running version of COMSOL Server™ in a web browser.
  2. Click the About COMSOL Server link in the lower-right corner.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Stop the COMSOL Server™ Processes

Before you proceed with the installation, make sure to stop any running COMSOL Server™ processes.

  1. In Windows®: Stop the server by either typing close, if COMSOL Server™ is running in a command window, or by running the Stop COMSOL Server shortcut from the COMSOL Launchers folder in the start menu, if COMSOL Server™ is installed as a Windows® service.
  2. In Linux®: If you configured COMSOL Server™ using the systemd service, stop it by typing systemctl stop comsolserver64; otherwise, kill the COMSOL Server™ process.
  3. In macOS: Kill the COMSOL Server™ process.
3

Install the Update

Before you proceed with the installation, make sure to stop any running COMSOL Server™ processes, as described above.

  1. Start the COMSOL® software update installer:
    • Windows® operating systems: Run the Update program from the COMSOL Launchers folder in the Start menu, or directly from the COMSOL 6.4 installation folder. The COMSOL Launchers folder can be found in the installation folder, for example, C:\Program Files\COMSOL\COMSOL64\Server\COMSOL Launchers.
    • Linux® operating systems: Run the update script from the COMSOL 6.4 installation directory, for example, /usr/local/comsol64/server.
    • macOS: Run the COMSOL Update application from the COMSOL 6.4 installation directory, for example, /Applications/COMSOL64/Server.
  2. The next step will be taken in the installer program\'s Options page and depends on whether or not you have a live internet connection or if you plan to download the update file for offline installation:
    • If you have an internet connection: Keep the Direct download setting.
    • If you have an internet connection via a proxy server: Select Download via proxy server and enter your proxy configuration settings.
    • If you do not have an internet connection on the target computer or if you want to apply the update several times on multiple computers: Download the following file to a folder on your computer
      DOWNLOAD UPDATE (6.5 GB)
      In the installer program, select Manual download and click Browse. Navigate to the downloaded file and click Open.
  3. Click Next to get to the Release Notes page for reviewing the update details.
  4. Click Next to get to the Install page and review the software components affected by the update.
  5. In the Install page, click Install to start the installation of the update.
4

Start COMSOL Server™ Again

  • In Windows®: Start COMSOL Server™ by using the COMSOL Server shortcut in the start menu. Alternatively, if COMSOL Server™ was installed as a Windows® service, start it by using the Start COMSOL Server shortcut.
  • In Linux®: If you configured COMSOL Server™ using the systemd service, start it by typing systemctl start comsolserver64; otherwise, type <installation directory>/bin/comsol server to start COMSOL Server™.
  • In macOS: Type <installation directory>/bin/comsol server to start COMSOL Server™.
5

Check the Installation

  1. Navigate to the running version of COMSOL Server™ in a web browser.
  2. Click the About COMSOL Server link in the lower-right corner
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)

Updating Model Manager Server

1

Check the Version Number

  1. Navigate to the running version of Model Manager server in a web browser.
  2. Click the About link in the center of the footer.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Stop the Model Manager Server Processes

Before you proceed with the installation, make sure to stop any running Model Manager server processes.

  1. In Windows®: Stop the server by either typing Ctrl+C, if Model Manager server is running in a command window or by running the Stop Model Manager Server shortcut from the COMSOL Launchers folder in the start menu, if Model Manager server is installed as a Windows® service.
  2. In Linux®: If you configured Model Manager server using the systemd service, stop it by typing systemctl stop comsolmodelmanagerserver64; otherwise, kill the Model Manager server process.
  3. In macOS: Kill the Model Manager server process.
3

Install the Update

Before you proceed with the installation, make sure to stop any running Model Manager server processes, as described above.

  1. Start the COMSOL® software update installer:
    • Windows® operating systems: Run the Update program from the COMSOL Launchers folder in the Start menu, or directly from the COMSOL 6.4 installation folder. The COMSOL Launchers folder can be found in the installation folder, for example, C:\Program Files\COMSOL\COMSOL64\ModelManagerServer\COMSOL Launchers.
    • Linux® operating systems: Run the update script from the COMSOL 6.4 installation directory, for example, /usr/local/comsol64/ModelManagerServer.
    • macOS: Run the COMSOL Update application from the COMSOL 6.4 installation directory, for example, /Applications/COMSOL64/ModelManagerServer.
  2. The next step will be taken in the installer program\'s Options page and depends on whether or not you have a live internet connection or if you plan to download the update file for offline installation:
    • If you have an internet connection: Keep the Direct download setting.
    • If you have an internet connection via a proxy server: Select Download via proxy server and enter your proxy configuration settings.
    • If you do not have an internet connection on the target computer or if you want to apply the update several times on multiple computers: Download the following file to a folder on your computer
      DOWNLOAD UPDATE (135 MB)
      In the installer program, select Manual download and click Browse. Navigate to the downloaded file and click Open.
  3. Click Next to get to the Release Notes page for reviewing the update details.
  4. Click Next to get to the Install page and review the software components affected by the update.
  5. In the Install page, click Install to start the installation of the update.
4

Start Model Manager Server Again

  • In Windows®: Start Model Manager server by using the Model Manager Server shortcut in the start menu. Alternatively, if Model Manager server was installed as a Windows® service, start it by using the Start Model Manager Server shortcut.
  • In Linux®: If you configured Model Manager server using the systemd service, start it by typing systemctl start comsolmodelmanagerserver64; otherwise, type <installation directory>/bin/comsol modelmanagerserver to start Model Manager server.
  • In macOS: Type <installation directory>/bin/comsol modelmanagerserver to start Model Manager server.
5

Check the Installation

  1. Navigate to the running version of Model Manager server in a web browser.
  2. Click the About link in the center of the footer.
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)

Setting up Automated Installation of the Update

If you do not have access to the graphical user interface of your operating system or if you want to automate the update process, you can follow the steps below.

Automated Update of COMSOL Multiphysics®

1

Check the Version Number

  1. Start COMSOL Multiphysics®.
  2. Open the About COMSOL Multiphysics dialog box. If using the Windows® operating system, the dialog box can be found in the File menu under Help. If using either the Linux® operating system or macOS, the dialog box can be found under the Help menu.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Download the Update File

Click the button below to download the update. In some browsers, such as the Internet Explorer® browser, a dialog box will then open where you can click Save directly after the download has occurred.

DOWNLOAD UPDATE (6.5 GB)

3

Installation

Before you proceed with the installation, make sure you have closed any COMSOL sessions or stopped any running COMSOL processes or any software you have running that correlates to a LiveLink™ product you would like to update (Excel®, MATLAB®, or a CAD software).

Windows® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = C:\Program Files\COMSOL\COMSOL64\Multiphysics
    installmode = update
    update.filepath = C:\Users\username\Downloads\comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Run cmd. Start the setup program (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: C:\Program Files\COMSOL\COMSOL64\Multiphysics\setup.exe -s C:\Users\username\setupconfig.ini

Linux® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /usr/local/comsol64/multiphysics
    installmode = update
    update.filepath = /home/username/Downloads/comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /usr/local/comsol64/multiphysics/setup -s /home/username/setupconfig.ini

macOS

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /Applications/COMSOL64/Multiphysics
    installmode = update
    update.filepath = /home/username/Downloads/comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /Applications/COMSOL64/Multiphysics/setup -s /home/username/setupconfig.ini

4

Check the Installation

  1. Start COMSOL Multiphysics®.
  2. Open the About COMSOL Multiphysics dialog box. If using the Windows® operating system, this is located in the File menu under Help. If using the Linux® operating system or macOS, this is located in the Help menu.
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)

Automated Update of COMSOL Server™

1

Check the Version Number

  1. Navigate to the running version of COMSOL Server™ in a web browser.
  2. Click the About COMSOL Server link in the lower-right corner.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Stop the COMSOL Server™ Processes

Before you proceed with the installation, make sure to stop any running COMSOL Server™ processes.

  1. In Windows®: Stop the server by either typing close, if COMSOL Server™ is running in a command window, or by running the Stop COMSOL Server shortcut from the COMSOL Launchers folder in the start menu, if COMSOL Server™ is installed as a Windows® service.
  2. In Linux®: If you configured COMSOL Server™ using the systemd service, stop it by typing systemctl stop comsolserver64; otherwise, kill the COMSOL Server™ process.
  3. In macOS: Kill the COMSOL Server™ process.
3

Download the Update File

Click the button below to download the update. In some browsers, such as the Internet Explorer® browser, a dialog box will then open where you can click Save directly after the download has occurred.

DOWNLOAD UPDATE (6.5 GB)

4

Installation

Before you proceed with the installation, make sure you have closed any COMSOL sessions or stopped any running COMSOL processes or any software you have running that correlates to a LiveLink™ product you would like to update (Excel®, MATLAB®, or a CAD software).

Windows® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = C:\Program Files\COMSOL\COMSOL64\\Server
    installmode = update
    update.filepath = C:\Users\\username\Downloads\comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Run cmd. Start the setup program (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: C:\Program Files\COMSOL\COMSOL64\Server\setup.exe -s C:\Users\username\setupconfig.ini

Linux® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /usr/local/comsol64/server
    installmode = update
    update.filepath = /home/username/Downloads/comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /usr/local/comsol64/server/setup -s /home/username/setupconfig.ini

macOS

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /Applications/COMSOL64/Server
    installmode = update
    update.filepath = /home/username/Downloads/comsol_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /Applications/COMSOL64/Server/setup -s /home/username/setupconfig.ini

5

Start COMSOL Server™ Again

  • In Windows®: Start COMSOL Server™ by using the COMSOL Server shortcut in the start menu. Alternatively, if COMSOL Server™ was installed as a Windows® service, start it by using the Start COMSOL Server shortcut.
  • In Linux®: If you configured COMSOL Server™ using the systemd service, start it by typing systemctl start comsolserver64; otherwise, type <installation directory>/bin/comsol server to start COMSOL Server™.
  • In macOS: Type <installation directory>/bin/comsol server to start COMSOL Server™.
6

Check the Installation

  1. Navigate to the running version of COMSOL Server™ in a web browser.
  2. Click the About COMSOL Server link in the lower-right corner
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)

Automated Update of the Model Manager Server

1

Check the Version Number

  1. Navigate to the running version of Model Manager server in a web browser.
  2. Click the About link in the center of the footer.
  3. Check that the version number is 6.4 (build 6.4.0.293 or 6.4.0.343). This corresponds to the version that has not yet been updated.
2

Stop the Model Manager Server Processes

Before you proceed with the installation, make sure to stop any running Model Manager server processes.

  1. In Windows®: Stop the server by either typing Ctrl+C, if Model Manager server is running in a command window or by running the Stop Model Manager Server shortcut from the COMSOL Launchers folder in the start menu, if Model Manager server is installed as a Windows® service.
  2. In Linux®: If you configured Model Manager server using the systemd service, stop it by typing systemctl stop comsolmodelmanagerserver64; otherwise, kill the Model Manager server process.
  3. In macOS: Kill the Model Manager server process.
3

Download the Update File

Click the button below to download the update. In some browsers, such as the Internet Explorer® browser, a dialog box will then open where you can click Save directly after the download has occurred.

DOWNLOAD UPDATE (135 MB)

4

Installation

Before you proceed with the installation, make sure you have closed any COMSOL sessions or stopped any running COMSOL processes or any software you have running that correlates to a LiveLink™ product you would like to update (Excel®, MATLAB®, or a CAD software).

Windows® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = C:\Program Files\COMSOL\COMSOL64\ModelManagerServer
    installmode = update
    update.filepath = C:\Users\username\Downloads\comsol_dbserver_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Run cmd. Start the setup program (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: C:\Program Files\COMSOL\COMSOL64\ModelManagerServer\setup.exe -s C:\Users\username\setupconfig.ini

Linux® Operating Systems

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /usr/local/comsol64/modelmanagerserver
    installmode = update
    update.filepath = /home/username/Downloads/comsol_dbserver_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /usr/local/comsol64/modelmanagerserver/setup -s /home/username/setupconfig.ini

macOS

  1. Create a file named setupconfig.ini in your home directory, or anywhere else you have write permission.

  2. Copy the following lines to setupconfig.ini
    installdir = /Applications/COMSOL64/ModelManagerServer
    installmode = update
    update.filepath = /home/username/Downloads/comsol_dbserver_6.4.0.378_update.dat

  3. Change installdir path to the target COMSOL installation. Change update.filepath to the path where the manual update file is located.

  4. Start the setup script (located in the COMSOL install directory) with the flag -s and the path to your setupconfig.ini file. Example: /Applications/COMSOL64/modelmanagerserver/setup -s /home/username/setupconfig.ini

5

Start Model Manager Server Again

  • In Windows®: Start Model Manager server by using the Model Manager server shortcut in the start menu. Alternatively, if Model Manager server was installed as a Windows® service, start it by using the Start Model Manager server shortcut.
  • In Linux®: If you configured Model Manager server using the systemd service, start it by typing systemctl start comsolmodelmanagerserver64; otherwise, type <installation directory>/bin/comsol modelmanagerserver to start Model Manager server.
  • In macOS: Type <installation directory>/bin/comsol modelmanagerserver to start Model Manager server.
6

Check the Installation

  1. Navigate to the running version of Model Manager server in a web browser.
  2. Click the About link in the center of the footer.
  3. Check that the version number is 6.4.0.378. (If not, the installation did not succeed.)
Linux is a registered trademark of Linus Torvalds in the U.S. and other countries. macOS is a trademark of Apple Inc., registered in the U.S. and other countries. Microsoft, Internet Explorer, Excel, PowerPoint, and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. MATLAB and Simulink are registered trademarks of The MathWorks, Inc.

All COMSOL® software products undergo stability improvements that are introduced as updates. The following list contains the most important improvements in COMSOL® version 6.4 update 2 (and update 1).

COMSOL Multiphysics

  • Solvers and GPU Acceleration
    • With version 6.4 Update 1, the NVIDIA CUDA® Toolkit has been upgraded to version 12.9.1 to enable full performance on NVIDIA Blackwell® GPUs, providing significantly improved GPU performance for DNN surrogate model training in the COMSOL Multiphysics® platform and for time-explicit acoustics simulations using the Acoustics Module.1
    • When using the NVIDIA CUDA® direct sparse solver (NVIDIA cuDSS), performance has been improved for the CPU-based parts of matrix factorization.1
    • Added support for NVIDIA cuDSS when running on clusters, including for Cluster Computing and Cluster Sweep studies2
    • When running on a computer with several graphics cards and at least one NVIDIA GPU, an NVIDIA GPU is selected for rendering.1
    • Fixed an issue that could prevent COMSOL Desktop® from starting on Windows® when an incompatible version of an OpenMP library was installed in the Windows System32 directory1
    • Cluster scalability has been improved.1
    • The solver performance issues that arose in some cases when Plot while solving was enabled and a Results Parameters node was present have been fixed.1
    • The storage format for Changes from Default Settings in solver features has been changed. Changes recorded in previous versions cannot be reverted by Undo Changes. Previously changed properties remain listed with unknown default values in the tables in the Changes from Default Settings section of the settings.1
    • The solver sequence now shows the storage format that will be used when running on a cluster.1
    • In all study types that use the eigenvalue solver, physics-controlled linearization points now use Automatic (all solutions) when the linearization point is a stored solution.2
    • Fixed a problem where parametric sweeps with part instances could run out of memory for a large number of parameter values2
  • The Chatbot Window
    • The OpenAI Responses API is now used when the Chatbot window is configured for OpenAI™ or Azure® OpenAI™.1
    • Updated the OpenAI Chatbot provider backend1
    • Resolved an issue when using Gemini™ 3 Pro Preview with the OpenAI API compatible provider1
    • The GPT-5 Low and GPT-5 High model options for OpenAI and compatible providers now use the GPT-5.4 version. Users that prefer previous GPT-5 versions can select the Custom model option and specify the additional settings.2
  • Functions and Operators
    • Fixed a plotting issue for Analytic functions using material properties when the model contains a Material Link1
    • The Interpolation function will no longer show a "No complex data allowed" error message when an ignored data column contains complex numbers.1
    • For the expression operator, detection of circular dependencies is now more robust.1
  • Reduced-Order Models (ROMs)
    • If a ROM is selected to reconstruct a physics interface’s dependent variables and the reduced-model data is cleared, the selection of the ROM is retained.1
    • It is now possible to export the particular solution from ROMs.1
    • In the Modal Reduction solver node, manually specifying an empty list of eigenpairs now leads to no eigenpairs being used. Similarly, in the Modal Reduction and POD Reduction solver nodes, manually specifying an empty list of constraint modes now leads to no constraint modes being used. 1
    • The column length of the projection matrix is now equal to the number of unreduced degrees of freedom.1
  • Results and Visualization
    • Evaluation of edges in shell datasets in 3D is now faster.1
    • Non-ASCII characters are now automatically supported in plot annotations with LaTeX enabled.1
    • Added support for Unicode in tooltips for 1D plots1
    • Fixed an issue with repeated headers in plot-data export of graph plots with multiple expressions1
    • For results features, updates after generating, updating, or deleting solutions are now faster.1
  • After Compact History has been used, unnecessary history entries are no longer created for image exports.1
  • An option to sort documentation search results by relevance has been added.1
  • The initial values for Global Dependent Variables now default to zero if not set.1
  • The quad-dominant mesh generator has been adjusted to avoid generating overly anisotropic quad elements in meshes with rapid element size transitions.1
  • Reduced the saving time of models with a large number of model tree nodes2
  • The Swept operation for meshing is now faster for geometries with many domains that have a common extrusion direction, as is often the case for ECAD models.2
  • Improved stability and performance for streamline plots2
  • Fixed an issue that could cause a crash when rendering on some graphics cards2
  • Performance improvements1
  • Stability improvements1,2
  • Cybersecurity improvements:
    • Removed the Apache Solr extraction module SolrCell (Apache Tika) to address the vulnerability reported in CVE-2025-665162
    • Upgraded Apache Log4j to version 2.25.3 to address the vulnerability reported in CVE-2025-681612
    • Upgraded Apache Tomcat to version 9.0.1152

Application Builder

  • Compilation of Method Editor code is now faster.1
  • A problem that sometimes caused incorrect initial window sizes in apps using subwindows has been fixed.1
  • Fixed a problem where checkboxes in tables in dialogs had to be clicked twice when changing the table selection2
  • Stability improvements1,2

Model Manager and File Handling

  • The Filters menu display of attributes with long labels has been improved.1
  • When saving models to files or database with built, computed, and plotted data excluded, binary table data is no longer deleted in cases where tables:1
    • Contain data imported from files
    • Are used by functions
    • Are used by plots

Model Manager Server

  • The configuration settings for a Model Manager server database added to the COMSOL Desktop® when running in client–server mode can now be remembered between different sessions of the COMSOL Multiphysics® server. These configuration settings are also available for other COMSOL processes running on the same server computer, for example, COMSOL batch processes launched while connected to the server. 1

AC/DC Module

  • Stability improvements1,2

Acoustics Module

  • For the Pressure Acoustics, Time Explicit interface, the underlying solver and data handling of the accelerated formulation has been improved for multiple GPUs and in cluster configurations. This improves overall simulation performance.1
  • The CFD Data (CGNS) function now supports NGON_n and NFACE_n element types.1 Corrected the expression for a results variable for evaluating the dissipated thermal energy associated with the Thermoviscous Boundary Layer Impedance condition1
  • Stability improvements1

Battery Design Module

  • Stability improvements1,2

CAD Import Module

  • Added support for importing ACIS® 2026 1.0 and SOLIDWORKS® 2026 files1
  • Stability improvements1

CFD Module

  • The CFD Data (CGNS) function now supports NGON_n and NFACE_n element types.1
  • The Use dynamic subgrid time scale and Limit small time steps effect on stabilization time scale checkboxes now affect the turbulence variables in the Reynolds-averaged Navier–Stokes, Reynolds stress model (RANS-RSM):1
    • Activating the checkboxes (separately or together) modifies the formulation for the consistent stabilization terms of the components of the Reynolds stress tensor equation and the turbulent dissipation rate or specific dissipation equation. Thus, stability of the turbulence equations of an RSM is not lost at small time steps. This update can be crucial in cases when flow is accompanied by fast and stable processes, which causes very small time steps, or when starting time-dependent studies, which also can result in very small time steps during initial iterations.
  • A rotation-curvature correction in k-based RANS models now allows combining rotating domains with stationary domains in Frozen Rotor studies.1
  • Stability improvements2

Chemical Reaction Engineering Module

  • There is now a volume density distribution result template available for the Size-Based Population Balance interface.1
  • Stability improvements1,2

Composite Materials Module

  • Stability improvements1

Corrosion Module

  • Stability improvements1

ECAD Import Module

  • Stability improvements1

Electrochemistry Module

  • Stability improvements.2

Fatigue Module

  • Stability improvements1

File Import for CATIA® V5

  • Added support for importing CATIA® V5 2026 files1

Fuel Cell & Electrolyzer Module

  • Stability improvements1

Granular Flow Module

  • Stability improvements1

Heat Transfer Module

  • When the parent interface of the Radiation Shield, Upside and Radiation Shield, Downside features is involved in any Heat Transfer with Surface-to-Surface Radiation multiphysics coupling, these features can only be applied to external boundaries of the associated Heat Transfer interface. Now, in addition, if that Heat Transfer interface is also involved in any Thermal Connection, Layered Shell, Surfaces multiphysics coupling or Thermal Connection, Nonlayered Shell multiphysics coupling with the Connection type set to Shared boundaries or Facing boundaries, the Radiation Shield, Upside and Radiation Shield, Downside features cannot be applied to boundaries selected by those multiphysics couplings.2
  • Stability improvements1,2

LiveLink™ for Excel®

  • Stability improvements1

LiveLink™ for MATLAB®

  • Stability improvements1

LiveLink™ for Simulink®

  • A corrupt file that resulted in the library blocks not showing up correctly in the Simulink® Library Browser has been replaced.1

LiveLink™ for Revit®

  • Stability improvements1

LiveLink™ for SOLIDWORKS®

  • LiveLink™ for SOLIDWORKS® is compatible with SOLIDWORKS® 2026 as of COMSOL Multiphysics® version 6.4 (build 6.4.0.293). This support applies to version 6.4 update 1 (build 6.4.0.343) and update 2 (build 6.4.0.378).1

LiveLink™ for Solid Edge®

  • Added support for synchronizing assemblies that include sheet metal parts saved as .psm files2

MEMS Module

  • Stability improvements1,2

Metal Processing Module

  • Stability improvements1

Mixer Module

  • Stability improvements1

Optimization Module

  • Fixed an issue that prevented the use of condition-based final time with shape- and topology-optimization study steps1
  • Stability improvements1,2

Particle Tracing Module

  • Stability improvements1

Pipe Flow Module

  • Stability improvements1

Plasma Module

  • Stability improvements1,2

Polymer Flow Module

  • Stability improvements2

Porous Media Flow Module

  • Stability improvements1

Ray Optics Module

  • Stability improvements1

RF Module

  • Stability improvements1,2

Rotordynamics Module

  • Stability improvements1

Semiconductor Module

  • A bug for the finite-volume formulation in the Semiconductor–Electrostatics Coupling feature has been fixed.1
  • The Semiconductor–Electrostatics Coupling feature now provides improved support for Frequency-Domain Perturbation studies.1

Structural Mechanics Module

  • Fixed a problem with the Flanagan–Belytschko method for hourglass stabilization when the Compute boundary fluxes checkbox has been selected in the Discretization settings for the Solid Mechanics, Explicit Dynamics interface1
  • Fixed an issue with the Boundary Load feature in the Solid Mechanics, Explicit Dynamics interface that prevented the use of the load type option Resultant2
  • Forces and moments from springs and dampers in the Spring Foundation node under Rigid Connector and Rigid Material in structural interfaces are now available in the global coordinate system. Use the variables fsx, fsy, fsz and msx, msy, msz to plot their respective components. Use fslx1, fslx2, fslx3 and mslx1, mslx2, msxl3 for the local coordinate system.2
  • Fixed an error in the definitions of local velocity and acceleration variables in the Beam interface for the quasistatic case2
  • Fixed a bug that could lead to undefined variables when using a reduced CMS component in geometrically nonlinear studies2
  • The definition of the connected region in the Solid–Thin Structure Connection and Layered Shell–Structure Connection multiphysics couplings has been updated to avoid overconstraint.2
  • Stability improvements1,2

Uncertainty Quantification Module

  • Stability improvements1,2

Wave Optics Module

  • Stability improvements1,2

1 New in update 1 (build 6.4.0.343, released January 29, 2026)

2 New in update 2 (build 6.4.0.378, released March 19, 2026)

Apache, Apache Solr, Apache Tomcat, Apache Tika, Log4j, and Tomcat are either registered trademarks or trademarks of the Apache Software Foundation. Autodesk, the Autodesk logo, and Revit are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and/or other countries. Gemini is a trademark of Google LLC. Linux is a registered trademark of Linus Torvalds in the U.S. and other countries. macOS is a trademark of Apple Inc., registered in the U.S. and other countries. MATLAB and Simulink are registered trademarks of The MathWorks, Inc. Microsoft, Azure, Excel, and Windows are trademarks of the Microsoft group of companies. NVIDIA and CUDA are trademarks and/or registered trademarks of NVIDIA Corporation in the U.S. and/or other countries. OpenAI is a trademark of OpenAI, Inc. Solid Edge is a trademark or registered trademark of Siemens Industry Software Inc., or its subsidiaries or affiliates, in the United States and in other countries. SOLIDWORKS is a registered trademark of Dassault Systèmes SolidWorks Corp.
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