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Engine version support
Mass Forge currently supports Unreal Engine 5.6, 5.7, and 5.8 on Win64. Each supported engine line is compiled from the same plugin source and must pass the complete release verifier before a Mass Forge release is published.
Verified matrix
| Unreal Engine line | Verified baseline | Platform | Editor | Development Game | Shipping Game | Automation |
|---|---|---|---|---|---|---|
| 5.6 | 5.6.1 (CL 44394996) | Win64 | Pass | Pass | Pass | 39/39 twice |
| 5.7 | 5.7.1 (CL 48512491) | Win64 | Pass | Pass | Pass | 39/39 twice |
| 5.8 | 5.8.2 (CL 56702186) | Win64 | Pass | Pass | Pass | 39/39 twice |
The current final-source matrix was executed on 2026-09-21. Every row used strict includes, disabled unity/shared PCH assumptions through BuildPlugin, required zero Mass Forge/test warnings or errors, and compared all 494 authored package files byte-for-byte. Each package was then installed into clean Blueprint and external C++ hosts; all three engines passed 115-asset validation, authored-content automation, Blueprint Quick Start runtime smoke, and isolated C++ Editor/Game builds.
Multiplayer is intentionally outside the supported initial-release scope. Existing networking source is available for evaluation but is not represented by this matrix and is not an advertised compatibility or support promise.
The exact patch versions above are the verified baselines. Later patch releases within the same engine line are intended to remain compatible, but are not described as verified until the matrix has run against them. Unreal Engine versions before 5.6, versions after 5.8, and non-Win64 targets are currently unadvertised rather than implicitly supported.
Compatibility approach
Mass Forge keeps one source tree for all supported engine lines. The compatibility boundary is isolated in Source/MassForge/Public/Compatibility/MF_MassCompatibility.h and the runtime module rules. UE 5.8 moved foundational Mass types into MassCore; earlier versions continue to use the original MassEntity headers. Public gameplay behavior and Blueprint APIs do not change across the matrix.
Source plugins compile against the consuming project's engine. Precompiled distributable binaries are engine-line-specific and are produced separately for 5.6, 5.7, and 5.8. Content originates from the UE 5.6 compatibility baseline; the 5.7 and 5.8 distribution copies are resaved by the matching engine in an isolated host and strictly revalidated, so customers do not receive an avoidable asset-update prompt. The normalized copies never overwrite the source-of-truth assets.
Release policy
Before advertising a new engine line or patch baseline:
- From a complete Mass Forge source checkout, run the repository-only
Scripts/Verify-MassForge.ps1against that exact engine installation. - Require strict Editor, Development Game, and Shipping Game success on Win64.
- Require the complete automation suite to pass twice with no Mass Forge/test warnings or errors.
- Confirm the package payload and cleanup audits pass.
- Record the exact engine version, changelist, date, and result in this matrix and the retained release evidence.
An engine line remains supported until a Mass Forge release note explicitly deprecates it. Deprecation must be announced before removal, include a migration recommendation, and never silently change an existing release's stated support.
Reporting compatibility issues
Include the exact Unreal Engine version and changelist from Engine/Build/Build.version, Windows version, Mass Forge version, build target, relevant log excerpt, and a minimal reproduction. If the issue occurs only on a newer engine patch, also state the nearest verified baseline that succeeds.