rivencraft/docs/MINECRAFT_26_3_PORT.md

Minecraft 26.3 port status (issue #96)

Checked 2026-10-26. Minecraft Java 26.3 is the newest stable Java release with NeoForge support. This is an engineering audit and the start of the port, not a claim that a 26.3 Rivencraft JAR is ready. The 1.21.1 build remains the release target until a separate 26.3 client and dedicated-server build passes. The user wants both Minecraft lines maintained after the port, not a one-time 26.3 release. Gitea milestone "Dual-version support: 1.21.1 and 26.3" tracks issues #97–#103 under parent #96.

Version boundary

Minecraft 26.3/NeoForge uses Java 25, while Rivencraft 1.21.1 uses Java 21. Build and publish separate artifacts; do not widen the Minecraft dependency range of the 1.21.1 JAR. The official 26.3 release notes, NeoForge 26.3 Maven metadata, NeoForge Java 25 setting, and NeoForge migration primers are the version sources. NeoForge 26.3.0.99 is the newest listed stable build at the time of this check.

Dependency availability

The entries below mean that a NeoForge 26.3 version is advertised by the project, not that its API or runtime behavior has been validated with Rivencraft. Recheck immediately before choosing versions for a port build.

Integration	Role in 1.21.1	26.3 availability	Port decision
Dynamic Dimensions AR Edition	Required runtime Age loading	No; 1.21.1 only	Keep it for 1.21.1. Use a Rivencraft-owned runtime-dimension backend for 26.3.
bad packets	Declared runtime dependency; no direct Java imports in Rivencraft	No advertised 26.3 version	Determine whether the new dimension backend needs it; otherwise remove it from the 26.3 artifact. Use NeoForge's own networking for Rivencraft packets.
JEI	Optional recipe/page guides	Yes	Port and test its plugin against the 26.3 API.
TerraBlender	Optional modded biome support	Yes	Port and verify biome discovery and Age generation.
Serene Seasons and GlitchCore	Optional seasons	Yes	Port and repeat the per-Age seasonal matrix.
Biomes O' Plenty	Optional TerraBlender test addon	Yes	Test modded biome registration and decoration.
Ruins (Structure Spawning System)	Optional authored ruins integration	Yes	Port and verify its generation hooks.
Create / bundled Ponder	Optional scene renderer	No advertised 26.3 version	Use Rivencraft's existing legacy-animation preview fallback for this target until a compatible release exists.
Immersive Portals for (Neo)Forge	Optional live views and portal teleport integration	No advertised 26.3 version	Use the fallback portal surface and normal Rivencraft linking. Do not claim live destination views on 26.3.

Ecliptic Seasons publishes 26.3, but Rivencraft's Ecliptic integration was deferred and is not a replacement for the current Serene integration.

The alternatives checked for runtime Age loading do not meet the 26.3 NeoForge requirement: upstream Dynamic Dimensions and its AR fork have no published 26.3 branch or artifact; DimLib is Fabric-only and stops at 1.21.1; and DimensionsCore currently publishes only a Forge 1.20.1 file. Mods that add fixed dimensions or portals do not supply the arbitrary per-book runtime worlds Rivencraft needs. This is a search result, not proof that no other project exists.

26.3 backend design

The 26.3 port is a fresh-save target. It does not need to import 1.21.1 Age worlds or migrate Dynamic Dimensions' saved registry data. The 1.21.1 artifact will continue using that library. Within 26.3, however, a created Age must retain its identity, seed, chunks and access across save/restart.

1. Keep the existing AgeDimensionService/AgeDimensionBackend boundary. Implement a target-specific 26.3 backend without importing Dynamic Dimensions or its seed mixin. The backend contract needs registration at server start, create/load, unload and delete. Return a failure without publishing a half-created Age if any step fails.
2. At server startup, reconstruct all non-retired Ages from Rivencraft's AgeRegistrySavedData before players can join. For a newly bound book, register its unique rivencraft:age/... dimension and construct a ServerLevel from its authored chunk generator, dimension type and saved Age seed. The seed must feed chunk random state, not only getSeed().
3. Register the level with the server's level map and the appropriate dimension registries, then synchronize the new dimension definition to already-connected clients before sending a travel packet. Handle a connecting client receiving every existing Age. Determine the minimal 26.3 registry and network hooks from the current NeoForge source; do not assume /reload creates new running levels.
4. Initialize world border, view/simulation distance, forced chunks, spawn settings, per-Age data storage and tick/save lifecycle as a normal level. On unload or retirement, refuse while players occupy the Age, move any remaining entities safely, flush pending chunk writes, detach the level, and synchronize removal. Retirement must not delete another Age's data.
5. Review the MIT-licensed Dynamic Dimensions code as an implementation reference. If any code is adapted, retain its copyright/license notice and identify the derived files. Prefer the smallest backend Rivencraft needs over a general-purpose library fork.

For gameplay systems, treat the 1.21.1 Rivencraft source and assets as the porting baseline. Carry across unchanged rules, probabilities, recipes, and textures directly; adapt only the Minecraft/NeoForge APIs that changed in 26.3. Record deliberate behavior gaps (such as prototype Age generation) instead of silently replacing established mechanics with new ones.

The release gate is a 26.3 integrated-client and dedicated-server matrix: create two Ages with distinct seeds, explore chunks, travel while another client remains online, reconnect, restart, revisit saved chunks, reseed for future chunks, unload/reload, retire one Age without harming the other, and verify normal travel without optional mods. Then repeat relevant paths with available integrations. A failed synchronization must be reported and leave the player in their current level, not crash or strand them.

Implementation order

1. Keep AgeDimensionService independent of a concrete runtime-dimension implementation. The 1.21.1 Dynamic Dimensions calls now live in AgeDimensionBackend; the AgeDimensionSeedMixin is 1.21.1-only.
2. Create a separate 26.3/Java 25 build target. Replace the dimension backend, then migrate the main sources through the official NeoForge primers. Do not publish a partial JAR with missing Age generation.
3. Port optional integration classes one at a time. Keep unavailable mods optional and preserve their existing fallbacks. Upgrade JEI, TerraBlender, Serene Seasons/GlitchCore, Biomes O' Plenty, and Ruins only in the 26.3 target; do not change the validated 1.21.1 dependency set.
4. Run compile, data/resource validation, new-world Age generation, Age save/restart/reload, direct and portal/book travel, client rendering, and dedicated-server tests on both targets. Test without optional mods, then with each available integration. Require an in-game check before release.

The core blocker is not a version number change: 26.3 makes a major API jump and the required 1.21.1 runtime-dimension library has no 26.3 build.

Build isolation started in #97

The repository root remains the playable 1.21.1/Java 21 build. A separate ports/mc263 Gradle build now resolves NeoForge 26.3.0.99 and compiles with Java 25. The build workflow has separate Java 21 and Java 25 jobs. Its JAR task remains disabled; this does not satisfy #97's final artifact criteria.

First core slice in #98

The 26.3 target now has real Rivencraft metadata and an entrypoint. It registers the Crystal Shard and Crystal Block with their reused 1.21.1 textures/models plus the 26.3 item-model definitions. build passed, and a dedicated development server loaded the mod and reached Done with a new world and no optional mods. The server was then stopped. This validates only the entrypoint/registry/resource foundation. A development client also loaded Rivencraft and reloaded its resources without reported missing models or textures. The client logged the host's missing libflite.so narrator library; this is unrelated to Rivencraft. Both test processes were stopped after startup. This does not validate in-world client rendering or Age functionality. Age generators, data, networking, and client code still need migration; #98 remains open.

Runtime-level prototype in #99

The 26.3 target has a first-party server-side runtime-level loader and a SavedData seed index. It constructs each level with a LevelStem seed override, publishes the level only after construction, and restores indexed Ages when the Overworld loads. A dedicated-server probe created two separate Ages with seeds 123456789 and 987654321; after generating chunks, their terrain fingerprints differed (2865094 and 3227421). Both levels, their region files, seeds, and fingerprints survived a server restart, and the startup log shows restoration before Done. The temporary operator-only rivencraft_port age command exists solely to test this non-distributable port workspace.

This is not issue #99 completion. The loader currently reuses the vanilla Overworld generator because issue #98 has not ported authored generators or Age definitions. The synchronized operator travel probe below does not port normal book travel. The 26.3 JAR task remains disabled.

Runtime client-catalog prototype in #100

The 26.3 target now sends the current dimension-key catalog to each joining client and broadcasts a new catalog when a prototype Age is created or retired. Clients update their known-level set and acknowledge a version; the server's rivencraft_port age enter <name> probe refuses travel until that acknowledgement arrives and the target is still loaded. A stale acknowledgement does not satisfy the gate. This follows NeoForge's play-payload registration and client-handler separation. It is not a general dynamic-registry sync for authored dimension types, which have not been ported.

The dedicated-server probe used two simultaneous 26.3 clients. Both acknowledged a newly created Age without reconnecting; a second client entered an existing runtime Age; a player saved inside an Age reconnected after server restart and remained there. The operator travel probe searches near origin for safe footing and creates a small Crystal Block platform if none is found. This probe is not the final book landing implementation.

rivencraft_port age retire <name> refuses to retire an Age containing a player, then saves and closes it, removes it from the active index, and broadcasts the reduced catalog. On the dedicated test server, the client acknowledged creation and retirement even when they happened back-to-back; a late acknowledgement for the intermediate catalog was ignored. Travel to the retired Age was refused without moving the player, and retiring an occupied Age was refused. The #101 lifecycle slice below now archives exact Age data.

This remains a prototype, not completion of #100: normal Linking and Descriptive Book travel, authored dimension-type/generator registration, full client registry synchronization, and an integrated-client regression pass must follow the core port. The 26.3 JAR remains disabled. The local test server was stopped after verification.

Runtime lifecycle prototype in #101

The operator-only backend probe now supports age unload, reload, reseed, and retire in addition to create, list, sample, and enter. Unload and retirement refuse a level containing players. A full chunk/entity save and close handles other entities; Minecraft's shutdown-style ticket deactivation and startup-style activation preserve forced chunks across runtime reloads. The loaded-dimension catalog is rebroadcast after unload/reload/reseed and retirement, with stale acknowledgements ignored.

On the dedicated server, a generated Age unloaded and reloaded with the same terrain fingerprint. Reseeding lifetest from 24680 to 13579 kept the previously generated origin fingerprint 2898472; previously ungenerated chunks at offset 100 produced fingerprint 2897795, identical to a fresh 13579 control Age and different from a fresh 24680 control (2863099). After restart, lifetest still reported seed 13579 and its original origin fingerprint. Three consecutive unload/reload cycles with a connected client completed; that client acknowledged the final catalog and intermediate stale acknowledgements were ignored. Unloading the player's current Age was refused.

A force-loaded chunk and a summoned armor stand with UUID [I; -872307724, 883641011, -1239011659, 796091120] survived repeated runtime unload/reload and server restart. The entity could be queried again after its chunk finished loading. The probe retired a different Age, seedcontrol: only its directory moved to the sibling world-retired-ages archive, other Age directories stayed in place, and reloading/recreating the retired ID was refused after restart. A second archival probe exercised the tombstone-before-move sequence and again moved only its own directory. The tombstone is persisted before the archive move so an interrupted archival cannot silently revive an old Age; an ordinary move failure attempts to restore the index and level. Ten more consecutive unload/reload cycles completed on the dedicated server, with its open file-descriptor count steady at 218 before and after. That is a narrow smoke check, not proof of no leak.

This still does not close #101. The prototype has not been integrated with normal books or the full 26.3 Age definition, nor has a long-running resource leak test or interrupted-archive recovery drill been completed. Its dev world and archive are under ignored ports/mc263/build, not a release save.

Optional-integration probe in #102

On 2026-10-27, the published NeoForge 26.3 versions checked were JEI 31.17.0.95, TerraBlender 26.3.0.0.9, Biomes O' Plenty 26.3.0.0.15, GlitchCore 26.3.0.0.5, and Serene Seasons 26.1.2.0.7 (its file is labelled for Minecraft 26.3). Ruins advertises 26.3.1NF. Create/Ponder and Immersive Portals still had no advertised compatible version. These are availability checks, not API-compatibility claims.

The 26.3 development target now has the operator-only /rivencraft_port compat command. It reports loaded optional mod IDs and the count of registered biome keys by namespace, so integration smoke tests can distinguish a missing addon from a missing biome registration. It does not change Age generation. A clean dedicated server loaded with no optional mods and reported 67 vanilla biomes. A separate dedicated-server launch with TerraBlender, Biomes O' Plenty, GlitchCore, and Serene Seasons loaded all four; the probe reported 68 biomesoplenty biome keys, and TerraBlender logged its Overworld and Nether regions. Both launches stopped cleanly.

Issue #102 remains open. The 26.3 target still lacks authored Ages, JEI guides, per-Age season policy, Ruins hooks, book previews and crystal portals, so the relevant integration and fallback acceptance tests cannot yet pass. The probe must not be mistaken for feature support. The existing 1.21.1 integration code and dependencies remain unchanged.

First player-facing bridge in #104

The 26.3 port now registers a Descriptive Book with the Legacy item texture and a persistent, network-synchronized Age-ID data component. The operator-only /rivencraft_port age book <name> probe grants a book for an already indexed Age; an unbound book does not create a world. Using the bound book calls the same server-authoritative, catalog-acknowledged landing path as the existing age enter probe. A missing or unloaded Age refuses travel. This avoids trusting a book-supplied seed or creating a new Age from a forged item.

The dedicated-server smoke test still passed after this bridge, and a 26.3 development client loaded the new item model and texture without a missing resource warning. The host still reports a missing Linux libflite.so narrator library; this is not a Rivencraft item error. The client was stopped. The player confirmed right-click travel in game. Book component persistence across restart still needs a player test; the headless smoke test cannot exercise it. To test the bridge in a disposable 26.3 world as an operator:

1. /rivencraft_port age create booktest 123456789
2. Wait for the Age catalog acknowledgement, then /rivencraft_port age book booktest.
3. Right-click the granted book and verify arrival in rivencraft:age/booktest. Restart client and server, then use the same book again and verify it targets the same saved Age.

This is deliberately a port probe, not the final book workflow: the Book Binder, naming UI, GUI preview, automatic return link, dropped-book entity, authored Age plan, and Legacy landing rules are not yet connected. The bound book currently remains in hand after travel. Do not distribute this target or mark #104 done. For a local player test only, the normally disabled port JAR can be built with ./gradlew -p ports/mc263 build -PallowIncompletePortJar=true; its filename retains 26.3-INCOMPLETE and a port-dev version marker. This does not enable the normal release artifact or imply that the full mod has been ported.

The first Prism test exposed a production-only catalog bug: Minecraft 26.3's ClientPacketListener.levels() returned an immutable set, and the client handler attempted to clear it. That threw UnsupportedOperationException before the client could acknowledge the Age, so book travel was refused. The handler now replaces the entire level set through a narrow access transformer and acknowledges only after replacement. The corrected local test JAR is rivencraft-26.3-INCOMPLETE-0.0.0.1-port-dev.jar. It built successfully; the player used that JAR to verify actual travel in game on 2026-10-27.

Linking Book return-path slice

The separate 26.3 target now registers a Linking Book using the Legacy bound book sprite. /rivencraft_port link book grants an operator-only probe book bound to the player's exact current dimension, coordinates, and facing. Its destination is a persistent data component resolved by the server on use. A missing dimension, unacknowledged catalog, same-dimension target without Intra-Linking, out-of-bounds target, or obstructed arrival is rejected without moving the player. This path does not generate a landing platform.

For a test, stand at an unobstructed spot in the Overworld and run /rivencraft_port link book. Create and bind an Age Descriptive Book using the steps above, travel into that Age, then right-click the Linking Book. It should return to the exact bound spot and facing. Same-dimension use should refuse. Repeat after a server restart to check component persistence. This slice is 0.0.0.2-port-dev and remains explicitly incomplete: normal crafting/binding, modifiers, book GUI, origin-drop entity, and safe fallback are still unported. The probe book remains in inventory after travel.

Age-index durability after the first in-game return-link check

The first return-link test exposed a recoverable prototype failure: Seamless Portals rejected a newly added runtime Age, the integrated server exited abnormally, and a second Age created just before the exit was not present in Rivencraft's saved index on restart. Its directory contained no saved chunks. The 0.0.0.3-port-dev slice flushes the index synchronously before announcing newly created Ages to clients. It also flushes reseed changes. The dedicated server smoke test now checks that both new Age IDs are already in the on-disk index before it issues stop, then verifies both seeds/terrain after a restart. This closes the ordinary interrupted-shutdown gap but is not a substitute for a power-loss durability test or integration with other mods' dynamic-dimension catalogs.

Handheld Linking Book binding slice

The 0.0.0.4-port-dev target adds a client-only book screen using the Legacy book artwork. An unbound Linking Book accepts a player-chosen title; a serverbound packet binds the held book to the player's current dimension, coordinates and facing only after checking the book, title length and empty target. A bound book opens the same screen and uses a server-validated destination-panel click for travel. This replaces the earlier direct item-use probe. The panel is a visible placeholder, not a live snapshot. The rotating preview, completed book behavior (including origin drop), recipe, modifiers, stand handling and other port systems remain unported.

To test this slice, use /give @s rivencraft:linking_book in a 26.3 test world, stand at the intended return point, right-click the unbound book, enter a name and bind. Travel to an Age, right-click the book again and click its right-hand destination panel. Verify the named book persists across restart, same-dimension travel is refused, and a replaced/removed held book cannot be bound or used by a delayed screen packet. Do not treat this partial target as a playable release.

The first 0.0.0.4-port-dev in-game right-click exposed a 26.3 screen API mistake: Screen.extractRenderStateWithTooltipAndSubtitles already calls extractBackground, so the screen's second call raised Can only blur once per frame. The 0.0.0.5-port-dev fix removes that duplicate background call. The next in-game check found that a bound Linking Book's right-hand panel did not trigger travel: its target component was persistent but lacked a network codec, so the client screen could not identify the book as bound. The 0.0.0.6-port-dev slice adds stream codecs for the Linking Book target and Descriptive Book Age ID. Server-side held-item and destination checks remain authoritative. This needs another in-game check before considering the slice validated. The 0.0.0.6-port-dev retest showed the bound-book panel but left-clicking did not even close the GUI. Minecraft 26.3's primary mouse button is InputConstants.MOUSE_BUTTON_LEFT (value 1), while the port handler still checked the 1.21.1 value 0. The 0.0.0.7-port-dev slice uses the 26.3 constant. This still requires in-game verification of the full click/travel path. The player confirmed the 0.0.0.7-port-dev bound Linking Book click/travel path passes in game on 2026-10-27. The 26.3 target remains incomplete and is not ready for a public release or closure of the parent port issue.

Explicit technical alpha exception

At the player's request, 1.0.1.2-alpha.1 packages this limited 26.3 port as an experimental alpha. It is not the full mod and does not pass the stable release gate above. The alpha label and release notes must state that Ages use prototype vanilla terrain, normal authoring and most content are absent, and worlds should be disposable or backed up. The 1.21.1 stable release remains independent; issues #96–#104 stay open until the full port and validation pass.

The next development slice, 1.0.1.3-alpha.1, adds a basic Descriptive Book screen and server-validated binding. Naming an unbound book creates a unique prototype Age with a random seed; clicking the bound book's placeholder panel uses the acknowledged-catalog travel gate. This is not authored Page binding or a live destination preview. The player confirmed the Descriptive Book binding and travel interaction in game on 2026-10-29.

The following 1.0.1.4-alpha.1 development iteration registers a small Rivencraft creative tab for the two Books, Crystal Block, and Crystal Shard. It builds and passes the dedicated-server Age smoke test. The player confirmed the tab and four entries in game on 2026-10-29. No Page categories or unported items are advertised in the 26.3 tab.

The next local 1.0.1.5-alpha.1 iteration selects Legacy's unwritten Linking Book sprite until a target is bound, then the bound sprite. It also restores the four-Crystal-Shard crafting recipe for a Crystal Block. Both changes passed the player's in-game visual/crafting check on 2026-10-29.

The local 1.0.1.6-alpha.1 iteration ports Budding Crystal and the four blue crystal growth stages, reusing the 1.21.1 sprites and vanilla amethyst growth/harvest rules. Crystal clusters yield Shards, but natural crystal formation generation remains unported. Test growth with a Creative or command-placed Budding Crystal; the player passed the in-game check.

The local 1.0.1.7-alpha.1 iteration adds one persistent Page item with unwritten and Link Panel variants. It reuses the existing Page/Link Panel artwork and exposes only the Link Panel variant in its own creative tab, matching the 1.21.1 separation of Link Pages from symbol pages. Blank Pages remain command-only bases; the Ink Mixer, Book Binder and symbol writing are not yet ported. The player passed the in-game visual and persistence check.

The local 1.0.1.8-alpha.1 iteration ports the Ink Vial item, its animated sprite, and the black-dye/glass-bottle/water-bucket crafting recipe. Using it with paper in the other hand prepares a Link Panel at the current 1.21.1 default cost of 2 ink from a 16-use vial. Ink remaining persists per vial; an empty vial yields a glass bottle. The Ink Mixer, configurable ink cost, and Book Binder remain unported. The player passed the in-game craft/use check.

The local 1.0.1.9-alpha.1 iteration ports the special shapeless leather + Link Panel recipe for an unwritten Linking Book. The 26.3 recipe serializer rejects blank Pages and extra ingredients and preserves a panel's custom name without carrying its Page identity onto the Book. No Link Panel modifiers are ported yet. The player passed the in-game crafting check on 2026-10-29. The full Book Binder GUI and Age authoring remain the next larger port step.

The local 1.0.1.10-alpha.1 iteration adds the first three Link Panel modifiers as a prerequisite to Binder authoring. All eight combinations of Disarm, Maintain Momentum, and Intra-Linking are testable in the Link Pages creative tab and persist as a synced component through leather crafting and book binding. The server uses the book's flags when linking: Intra-Linking allows same-dimension travel, Maintain Momentum rotates horizontal velocity to the destination yaw, and Disarm drops player inventory at the departure point only after a successful teleport. The Ink Mixer, additional Link Modifier flags, and Descriptive Book panel propagation are not yet ported. In-game testing of each modifier and their combinations passed in game. This local slice must not be committed, pushed or published without the player's explicit request.

The next local 1.0.1.11-alpha.1 slice introduces the Book Binder block and its first server-authoritative binding workflow. Leather and a Link Panel produce a named, bound Descriptive Book for a random prototype Age; the output is persisted in the Binder until collected. The panel's Disarm and Maintain Momentum flags carry onto the book and apply after successful Age travel; Intra-Linking is inert for Descriptive Books. This is not yet symbol-page authoring or the full Legacy Binder interface. Build and dedicated-server smoke pass. The player passed basic Binder crafting and travel in game, but reported that typing E closed the GUI and asked us to reuse the 1.21.1 GUI more faithfully. No commit, push, or publication without an explicit request during alpha.

The local 1.0.1.12-alpha.1 follow-up ports the existing Binder layout's top title field, flank slots, center Page strip, and pulsing red missing-panel cue. It persists the title on the block entity and consumes focused keyboard events before the container can treat E as inventory-close. Click the output once to bind and again to collect the result. The full authored-symbol strip and 1.21.1 grammar still await later port slices. The same slice adapts the existing 1.21.1 Ink Mixer block, persistent basin, additive probabilities, 16-ink-per-panel exchange, virtual output, Legacy atlas and animated glyph to the 26.3 storage, menu and GUI APIs. The build and dedicated-server Age smoke pass. In-game Binder and Mixer verification is pending; do not commit, push, or publish without explicit authorization.

The local 1.0.1.13-alpha.1 iteration moves the Binder's freshly assembled book directly to the cursor so one output click both binds and takes it. Its central strip now displays five Legacy page thumbnails, while only the Link Panel is currently writable. The Mixer recomputes its virtual output in the same server click as an input change to address an intermittent first-attempt delay. The user's second Mixer attempt succeeded but exposed a cost mismatch: the Mixer now spends one ink and one paper per Link Panel and resets its additive chances on output pickup. Build passes; in-game retest is pending. This alpha remains local until explicitly authorized for release.

The local 1.0.1.14-alpha.1 visual follow-up uses the new Binder dev images as a reference: the page strip now grows only when a Link Panel is present or carried, its required-panel cue appears above the strip, and the first page can be clicked to place/take the panel. The stored page has a tooltip. The rest of the 1.21.1 strip (symbol pages and scrolling) depends on porting the symbol-page data and authoring pipeline, not just drawing more placeholders. The local 1.0.1.15-alpha.1 follow-up changes the missing-panel cue to the Link Panel's 16×16 item icon while preserving its red pulse and tooltip.

The local 1.0.1.33-beta.1 slice adds Flat and Void terrain to authored Binder books. Flat uses vanilla superflat layers and can use one authored Biome; Void generates no terrain but can use one authored Biome for environmental behavior. Without a Biome page, Void uses minecraft:the_void. Books with multiple Biome pages and Flat/Void terrain remain unassembled until their custom distribution generator is ported. The dedicated-server smoke creates, samples, and reloads both terrain families in a disposable world.

The local 1.0.1.34-beta.1 follow-up moves Flat ground to Y=0 and targets its surface for travel. 1.0.1.35-beta.1 enables the selected biome's decoration on Flat. 1.0.1.36-beta.1 ports a multi-biome Flat/Void chunk generator and accepts the existing authored distribution pages for those terrains. New Flat chunks can vary vegetation by biome; Void keeps biome climate without adding a floor or decorations. These are beta-port slices, not full 1.21.1 parity.

The local 1.0.1.37-beta.1 slice ports Cave terrain authoring using the 26.3 caves noise preset. Cave and Nether Biome pages can be distributed through an Age, and travel searches for footing from Y=64 downward rather than mistaking the cave roof for the surface. Nether-style cave material replacement from 1.21.1 remains a separate port task. The local 1.0.1.38-beta.1 follow-up keeps Cave Ages dry by default: the vanilla 26.3 Cave preset otherwise fills low openings with water. This changes newly generated chunks only; a future Flooded page will deliberately set an authored water level in both maintained versions. The local 1.0.1.39-beta.1 follow-up makes the 26.3 landing search reject fluid at feet and head height and prevents a submerged fallback platform.

The local 1.0.1.40-beta.1 slice gives pageless Descriptive Books a seed-selected terrain and biome plan. It follows the 1.21.1 rank weights for terrain and biome distribution, selects registered Cave/Nether biomes for Cave Ages and overworld-source biomes for other non-Void terrains, and persists the resolved choices. Other random Age traits remain a later port task.

The local 1.0.1.41-beta.1 slice adds the first Age-scoped feature wrapper to the 26.3 generator. A Block page followed by Rocks now places clusters of the chosen block in new Standard, Amplified, Island, or Flat terrain chunks. The Age index persists that selection, and the wrapper delegates all vanilla terrain, biome, and structure generation. Cave and Void are intentionally excluded until their feature placement rules are ported. This is not yet the full 1.21.1 feature grammar or instability system.

Verification of this first slice

The 1.21.1 compileJava and build tasks passed offline after the backend extraction. The GameTest server ran 93 tests; 92 passed, while twoblockdeskdropsonce failed because breaking either desk half dropped zero desks instead of one. That desk failure is outside the dimension-backend edit and must be resolved or rechecked before a release. The 1.21.1 build task passed again after the 26.3 registry slice.