Close all Mitsubishi software including GX Works2/3, GT Simulator3, and Melsoft Navigator.

The update addresses known vulnerabilities, ensuring secure data communication between the HMI and PLC.

In the download center search bar, type: GT Designer3 Version 1.280S . Filter the results by and Updates/Patches .

If this is a fresh installation, enter your registered Melsoft Product ID when prompted. If it is an update, the software will automatically validate your existing license.

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