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ZQEL Licensing

ZQEL is available under a dual-licensing model:

  • Community and noncommercial use under the PolyForm Noncommercial License 1.0.0.
  • Commercial use under a separate commercial license granted by the ZQEL Licensor.

The purpose of this model is to keep ZQEL freely available for education, research, personal use, experimentation, and other permitted noncommercial purposes, while requiring organizations that commercially benefit from the use of ZQEL to obtain a commercial license.

Licensor

For the purposes of this licensing policy and any reference to the “Licensor”, the Licensor is:

Michael Protogerakis Lindener Str. 156 52146 Würselen Germany

Unless expressly agreed otherwise in writing, commercial licenses for ZQEL are granted by the Licensor identified above.

1. Community and Noncommercial Use

ZQEL is available under the PolyForm Noncommercial License 1.0.0.

Subject to the terms of that license, ZQEL may be used without a commercial license for permitted noncommercial purposes, including:

  • personal use;
  • education and teaching;
  • academic research;
  • experimentation;
  • evaluation for noncommercial purposes;
  • modification and development of ZQEL;
  • development and use by educational institutions and public research organizations where permitted by the PolyForm Noncommercial License.

The complete and authoritative terms of the PolyForm Noncommercial License 1.0.0 are contained in the LICENSE file.

In case of any conflict between this explanatory document and the PolyForm Noncommercial License, the terms of the PolyForm Noncommercial License govern use under the community license.

2. Commercial Use

Use of ZQEL for a commercial purpose is not granted by the community license and requires a separate Commercial License from the Licensor.

Commercial use includes, without limitation, using ZQEL to:

  • develop software for commercial products or services;
  • generate Rust, Structured Text (ST), or other implementation code for commercial products or services;
  • compile or translate ZQEL specifications as part of a commercial development process;
  • verify, validate, test, analyze, optimize, or maintain software for a commercial purpose;
  • synthesize implementations for commercial use;
  • develop PLC, embedded, control, automation, or other software deployed in commercially supplied machines, plants, devices, or systems;
  • perform engineering, consulting, integration, or development work for paying customers;
  • operate ZQEL as part of an internal commercial software-development or engineering process;
  • incorporate ZQEL itself into another commercial product or service;
  • provide functionality based on ZQEL as part of a paid product or service.

A commercial use does not become noncommercial merely because ZQEL itself is not shipped with the resulting product.

For example, using ZQEL during development to generate or verify Structured Text that is subsequently deployed on a PLC constitutes commercial use of ZQEL when that development is performed for a commercial purpose.

3. Generated Output

Programs, source code, binaries, configuration files, verification artifacts, certificates, reports, and other output generated using ZQEL are not subject to the ZQEL license solely because they were generated using ZQEL.

The Licensor claims no copyright or ownership in such output solely by reason of its generation using ZQEL.

This provision does not grant any additional right to use ZQEL itself.

Using ZQEL to develop, generate, compile, translate, verify, validate, test, analyze, optimize, maintain, synthesize, or otherwise produce or process software for a commercial purpose requires a valid Commercial License.

Once output has been lawfully generated using ZQEL under the applicable license, that output may be used, modified, distributed, sublicensed, and commercially exploited independently of ZQEL, subject to applicable third-party rights and licenses.

Accordingly, a commercial ZQEL license generally applies to the use of the ZQEL toolchain, rather than imposing a license requirement on each machine, PLC, device, or other product containing code generated by ZQEL.

4. Runtime and ZQEL Components in Generated Output

The preceding section applies to output created by ZQEL that does not itself contain ZQEL software.

Generated output may in some circumstances include, link against, incorporate, or depend upon runtime libraries, support code, templates, libraries, or other components distributed with ZQEL.

Such components remain subject to their respective license terms.

Where ZQEL generates self-contained Rust, Structured Text, or other implementation code without incorporating separately licensed ZQEL components, no ZQEL runtime license is imposed on that generated code merely because ZQEL generated it.

The applicable license of any runtime or support component distributed with ZQEL will be identified with that component.

5. Commercial Licenses

Commercial licenses are available separately from the Licensor.

A Commercial License may grant rights including:

  • commercial development and production use;
  • individual developer licenses;
  • team or site licenses;
  • organization-wide or enterprise licenses;
  • CI/CD and automated build-system use;
  • network or floating licenses;
  • OEM and redistribution rights;
  • integration of ZQEL into third-party toolchains;
  • support and maintenance;
  • long-term support releases;
  • additional verification or synthesis functionality;
  • warranties or other contractual assurances.

Commercial license terms, pricing, duration, licensed users, permitted installations, and enabled features are governed by the applicable Commercial License Agreement or order.

Nothing in this document establishes a particular pricing model or license fee.

6. Evaluation by Commercial Organizations

Making the source code publicly available does not by itself grant commercial-use rights.

Commercial organizations may inspect the publicly available source code to the extent permitted by the applicable license.

Evaluation, testing, proof-of-concept work, benchmarks, pilot projects, or other use by a commercial organization must comply with the PolyForm Noncommercial License or an applicable evaluation or Commercial License.

Where the intended evaluation is not permitted by the PolyForm Noncommercial License, the Licensor may provide a separate evaluation license.

7. Research and Education

ZQEL is intended to remain readily accessible for research and education.

Educational institutions, public research organizations, researchers, educators, and students may use ZQEL without a Commercial License to the extent their use is permitted by the PolyForm Noncommercial License 1.0.0.

Commercial projects performed by or together with educational or research institutions may require a Commercial License depending on the nature of the use and the applicable license terms.

8. License Enforcement

Commercial features or distributions of ZQEL may use technical license-management mechanisms.

These may include:

  • signed license files;
  • cryptographic hardware tokens;
  • hardware-backed keys;
  • machine-bound licenses;
  • network or floating-license servers;
  • CI/CD credentials;
  • organization or site licenses.

The presence or absence of a technical license check does not alter the rights granted by the applicable license.

Circumventing a technical license mechanism does not grant rights that are otherwise excluded by the applicable license.

9. Third-Party Software

ZQEL may use, invoke, link against, or distribute third-party software.

Examples may include SMT solvers, verification tools, compilers, libraries, and other components of the ZQEL toolchain.

Third-party components remain subject to their respective licenses.

The ZQEL license does not replace, modify, or supersede the license terms applicable to those components.

Users and distributors are responsible for complying with applicable third-party license requirements.

10. Contributions

Contributions to ZQEL may be subject to separate contribution terms or a Contributor License Agreement (CLA).

Such terms may require contributors to grant the Licensor sufficient rights to:

  • distribute contributions as part of ZQEL;
  • provide ZQEL under the community license;
  • provide ZQEL under commercial licenses;
  • relicense ZQEL in the future.

The applicable contribution terms are described in CONTRIBUTING.md and, where applicable, the ZQEL Contributor License Agreement.

Submitting a contribution does not alter the license applicable to ZQEL except as expressly provided by those contribution terms.

11. Future Licensing

The Licensor may release future versions of ZQEL under different or additional license terms.

In particular, the Licensor may choose to make future versions available under a more permissive open-source license such as Apache License 2.0, MIT, or another open-source license.

This allows the licensing model to become more permissive in the future without requiring the current commercial licensing model to be permanent.

Versions already distributed remain available under the license terms under which they were distributed.

Nothing in this section obligates the Licensor to change the license of any future version.

12. No Implied Commercial Rights

Access to ZQEL source code, possession of a copy of ZQEL, or the ability to build or execute ZQEL does not imply a right to use ZQEL commercially.

Likewise, the fact that generated Rust, Structured Text, binaries, or other output may be distributed independently does not grant a right to use ZQEL commercially to create that output.

Commercial rights must be obtained separately where required.

13. Licensing Questions

If you are unsure whether a particular use of ZQEL requires a Commercial License, contact the Licensor before using ZQEL for that purpose.

Commercial licensing arrangements may be tailored to individual developers, companies, research collaborations, engineering organizations, OEMs, tool vendors, and other use cases.

Summary

Noncommercial use

→ PolyForm Noncommercial License 1.0.0 → Free where permitted by that license.

Commercial use of the ZQEL toolchain

→ Separate Commercial License required.

Rust, Structured Text, or other code generated by ZQEL

→ Not subject to the ZQEL license merely because it was generated by ZQEL.

Commercial generation, verification, synthesis, compilation, or processing of that code using ZQEL

→ Commercial License required.

Third-party components

→ Governed by their respective licenses.

Future versions

→ May be released under more permissive terms at the Licensor’s discretion.