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Platform Support Matrix

Scope: Repository-wide platform, Minecraft version, and Java runtime compatibility. Requirement: REQ-RTP-SYS-001 (Java 21+ required), ADR-021 (legacy MC and Java out of scope), ADR-033 (NeoForge in scope), ADR-036 (network mode / proxies). Rule: Every cell is explicitly classified as Tested, Best-effort, or Unsupported. No cell may say "should work".

1. Classification Definitions

  • Tested: Verified by continuous or scheduled automated CI pipelines (including the nightly multi-node devstack acceptance harness, dedicated carrier compilation/unit suites, or multi-release ArchUnit/mock gates). Regressions in tested environments block release.
  • Devstack Scheduled Acceptance (Nightly): Paper, Folia, Fabric, and Velocity on Java 21 LTS (multi-node containerized integration with Redis, cross-server token flow, and lifecycle verification).
  • CI Build & Adapter Gates (Every Commit): Compiles, tests, and enforces architectural invariants across all active carrier modules.
  • Best-effort: Compatible architecture or downstream fork sharing the execution path of a tested platform, but lacking dedicated automated end-to-end integration runs in CI on every commit/night. Community bug reports are accepted and addressed, but fixes are prioritized behind tested platforms.
  • Unsupported: Incompatible threading models, missing required platform APIs, unsupported Java versions (< 21), or platforms explicitly declared out of scope (e.g. legacy Forge <= 1.20.1, Sponge, Bedrock-native). Bug reports on unsupported platforms are closed without investigation.

2. Java Runtime Support

RTP requires Java 21 or higher across all platforms and components (REQ-RTP-SYS-001).

Java Version Support Status Notes
Java 21 LTS Tested Primary reference runtime. CI default and base compilation bytecode target across all modules and devstack.
Java 22 Best-effort Non-LTS release; verified compatible with standard JVM language features.
Java 23 Best-effort Non-LTS release; compatible with JVM toolchains.
Java 25+ Tested Secondary CI toolchain in .github/workflows/gradle.yml and devstack for modern experimental carriers (e.g. MC 26.x unobf Mojmap carriers).
Java <= 20 Unsupported Fails closed on initialization. Modern language features, records, and virtual threads require Java 21+.

3. Platform x Minecraft Version Matrix

3.1 Backend Platforms (Server JVMs)

Minecraft Version Paper (+ forks) Folia Spigot Fabric NeoForge
MC 26.x (26.1, 26.2, 26.3+) Best-effort Best-effort Best-effort Tested Best-effort
MC 1.21.x (1.21.0 - 1.21.4+) Tested Tested Best-effort Tested Best-effort
MC 1.20.5 - 1.20.6 Tested Tested Best-effort Tested Unsupported
MC 1.20.0 - 1.20.4 Tested Tested Best-effort Tested Unsupported
MC 1.19.4 and older Unsupported Unsupported Unsupported Unsupported Unsupported

Platform-Specific Notes:

  • Paper & Forks (Leaf, Leaves, Purpur, Pufferfish, Airplane, DivineMC):
  • Status: Tested (Paper on 1.20.x, 1.21.x via automated build gates and nightly devstack); Best-effort (downstream forks and MC 26.x tracking).
  • Uses native Paper asynchronous chunk loading (World.getChunkAtAsync). Linear (.linear / ZSTD) worlds are supported through the live async chunk load path; core does not pre-filter .linear files unless an addon registers a reader (ADR-077).
  • Folia:
  • Status: Tested (1.20.x, 1.21.x via automated build gates, thread affinity ArchUnit rules, and nightly devstack).
  • Operates strictly under Folia Region & Entity schedulers with Count-Bound task pipelines (ADR-004, ADR-015). Off-tick Anvil pre-filtering on common pool avoids cross-region hops.
  • Spigot:
  • Status: Best-effort (1.20.x, 1.21.x; compiles via rtp-bukkit adapter and unit tested, but lacks scheduled live multi-server devstack verification in CI).
  • Uses background Anvil (.mca) parser for off-tick candidate pre-filtering to prevent main-thread chunk load stalls (S-005).
  • Fabric:
  • Status: Tested (1.20.x, 1.21.x, 26.x via Loom carrier build suites, Java 25 toolchain gates, and nightly devstack).
  • First-class Loom-remapped obf and Mojmap-unobf carrier modules with native async chunk futures (ServerLevel.getChunkSource().getChunkFuture) and FabricScheduler.
  • NeoForge:
  • Status: Best-effort (1.21.x, 26.x; compiles via rtp-neoforge ModDevGradle carrier and passes unit suites; scheduled live container acceptance is pending devstack phase 2).
  • Native ModDevGradle Mojmap runtime mod with NeoForgeScheduler and Brigadier command adapter (ADR-033). Legacy Forge (<= 1.20.1) is explicitly Unsupported.

3.2 Proxy & Network Platforms

Proxy Software Proxy Version Support Status Notes
Velocity 3.3.x+ Tested Primary reference proxy platform. Implemented in rtp-proxy-velocity with Redis/SQL state binding, reservation-token lifecycle, and devstack acceptance harness.
BungeeCord Modern (1.20+) Best-effort Supported via backend plugin-messaging transport (bungeecord:main channel). Dedicated proxy module (rtp-proxy-bungee) planned for Phase 3.
Waterfall Final release Best-effort BungeeCord fork; shares plugin-messaging transport path.
Travertine / HexaCord Any Unsupported Legacy protocol proxies incompatible with modern networking and Java 21.

3.3 Hybrid & Modded Server Runtimes

Platform Support Status Notes
Mohist (1.20.x, 1.21.x) Best-effort Bukkit/Forge hybrid. Executes via Spigot adapter path with Anvil pre-filtering.
Arclight (1.20.x, 1.21.x) Best-effort Bukkit/NeoForge hybrid. Executes via Spigot adapter path.
Sponge / SpongeForge Unsupported Incompatible plugin architecture; no Bukkit or Fabric SPI compatibility.
Magma / Banner Unsupported Unverified stability on modern Java 21 / hybrid threading.

4. Verification & Continuous Validation

Support classifications are backed by automated verification tiers:

  1. Build & Unit Test Verification:
  2. Run on every commit via GitHub Actions (.\gradlew build / ./gradlew build).
  3. Validates all platform carriers (rtp-bukkit, rtp-paper, rtp-folia, rtp-fabric, rtp-neoforge, rtp-proxy).
  4. ArchUnit Prohibition Enforcement:
  5. Verifies architectural boundaries: no platform leaks into rtp-core or rtp-api, zero main-thread synchronous chunk loading (S-005), and strict thread scheduling compliance.
  6. Multi-Server Acceptance Devstack:
  7. Boots multi-node Docker Compose network: 1 Redis + 2 Velocity proxies + 2 Paper backends + 1 Folia backend + 1 Fabric backend.
  8. Executes cross-server reservation token redemption, timeout reaping, and failover validation.