Untold Engine is open source under the Mozilla Public License 2.0 (MPL-2.0), which requires that modifications to MPL-covered engine files be made available when those files are distributed.
If you need to modify the engine privately — without disclosing your changes or contributing them back — a Commercial License is available.
If your use case involves modifying engine source files and keeping those changes private, a Commercial License is required.
- Modify engine source code and keep those changes proprietary
- No obligation to open-source or contribute modifications back
- Distribute your products without source disclosure requirements
- Covers unlimited Licensee Products for the licensed studio/team
- Priority triage for confirmed engine bugs
| Use case | Open Source (MPL-2.0) | Commercial License |
|---|---|---|
| Build games or apps with the engine | Yes | Yes |
| Modify engine files, keep changes private | No | Yes |
| Embed modified engine in a closed-source product | No | Yes |
| Use engine unmodified in a commercial product | Yes | Yes |
| Priority triage for confirmed engine bugs | No | Yes |
| Tier | Who it's for | Bug acknowledgement | Fix targeting | Support channel |
|---|---|---|---|---|
| Indie | Solo dev or 2-person team | 48 business hours | Next minor release | GitHub Issues (include tier) |
| Studio | Up to 8 developers | 24 business hours | Next patch release | GitHub Issues (include tier) |
| Enterprise | 8+ devs / embedded products | Custom SLA | Negotiated | GitHub Issues (include tier) |
Important: The Commercial License grants you the right to modify the engine privately. It does not entitle you to support for those modifications. Support covers the unmodified engine only. If you modify the engine and something breaks, that is outside support scope.
Support covers correctness bugs — incorrect or crashed behavior reproducible on an unmodified version of the engine. Not every report qualifies:
| Issue type | Covered |
|---|---|
| Correctness bug (crash, wrong output on device) | Yes — priority queue |
| Performance issue (correct output, lower throughput) | Best effort — documented regressions from a previous engine version may be escalated; workload-specific optimization is consulting unless otherwise agreed. |
| Platform-specific issue (visionOS, tvOS quirks) | Partial — triaged to confirm engine vs SDK root cause |
| Large scene / stress failure | Partial — requires minimal repro attempt |
| Feature gap (desired feature not in licensed version) | No — logged as feature request |
| Issue only present after your engine modifications | No — outside support scope |
Issues caused by your own modifications to engine internals are outside support scope.
Engine bugs reported by Commercial License holders take priority over all community (MPL-2.0) issues and feature requests.
Out-of-scope issues (e.g. debugging your custom modifications) may be addressed as paid consulting — contact harold.serrano@untoldengine.com to inquire. See LICENSE-COMMERCIAL-SUPPORT for full triage and scope details.
Contact Untold Engine Studios to discuss pricing and terms:
Note: The Commercial License is separate from GitHub Sponsorship. Sponsorship helps support and influence the project, but it does not grant commercial licensing rights or change the terms of the MPL-2.0 license.
Full license terms: LICENSE-COMMERCIAL Support policy: LICENSE-COMMERCIAL-SUPPORT