https://opcfoundation.org/license/source/1.11/index.html


      License information for OPC Source Deliverables


        A. Introduction

The OPC Foundation provides source code as sample code/reference
implementation. The source code is provided as-is, with no warranty,
support, or misrepresentation of the quality of code.

The OPC Foundation provides communication stacks, sample libraries,
sample applications and utilities. All sources are available either as a
downloadable ZIP file or in a repository on github
(https://github.com/OPCFoundation/ <https://github.com/OPCFoundation/>).


        B. License models

The OPC Foundation provides different licenses depending on the
component and on the membership status of the user of the sources. A
single ZIP file or a single repository can contain multiple components
where the sources have different license models. The valid license is in
the header of each source file.

Following are basic rules on how the OPC Foundation licenses the
different components:

 1. OPC UA core components (OPC UA Stacks, OPC UA Local Discovery Server
    - LDS) follow a dual-license model:
      * *OPC Foundation Corporate Members*: RCL
        <https://opcfoundation.org/license/rcl.html>
        enables OPC Foundation corporate members to deploy their
        applications using the core component sources without being
        required to disclose the application code.
         
      * *Users that are not OPC Foundation corporate-members*: GPL 2.0
        <https://opcfoundation.org/license/gpl.html>
        Based on the GPL 2.0 license terms these users must disclose
        their application code when using the core component sources.
         
 2. Samples and Utilities:
    All samples and most of the utilities are provided under the MIT
    license <https://opcfoundation.org/license/mit.html> for OPC
    Foundation Members and Non-Members.