Instant World Mirror 1.4.0 Beta

Instant World Mirror 1.4.0 Beta

This public Beta adds the Stranded Mirror cross-save workflow, persistent-world backups, and the Heaven Mirror Superflat enchantment matrix. Both supported Minecraft versions use the same player-facing behavior.

Stranded Mirror

• Added the Stranded Mirror for capturing named world slices and reopening them from other saves.
• Unified persistent mirror worlds and cross-save world slices in the long-term world menu.
• Added independent numbered backups for world slices and persistent mirror worlds.
• Backups preserve block entities, supported entities, distant modified chunks, item data, names, and enchantments without changing the source.
• Added one-way Minecraft 1.20.1 to 1.21.1 slice upgrades using Minecraft DataFixer validation.
• Newer slices remain blocked on 1.20.1, and missing mod content fails safely instead of silently becoming air.
• Fixed the slice-opening flow so success closes the complete menu and a rejected open keeps the selection screen usable.

Heaven Mirror Superflat

• Added the Superflat enchantment exclusively for Heaven Mirror.
• No enchantments: creates the normal temporary copied Heaven world.
• Superflat only: creates a temporary Superflat Heaven world.
• Permanence only: retains the normal temporary copied world and existing persistent-save workflow.
• Permanence plus Superflat: retains the normal temporary copied world and adds one automatic persistent Superflat world.
• Reusing the double-enchanted mirror does not create duplicate automatic Superflat records.
• Superflat platforms use grass, two dirt layers, and bedrock.

Persistent Worlds

• Added backup controls to the persistent list and in-world management menu.
• Persistent records retain their terrain mode and recover safely after interrupted copies.
• Generated persistent records no longer store a fake temporary-session identifier; existing records remain compatible.
• A persistent source cannot be deleted while one of its backups is still copying.

Downloads

• instantworldmirror-1.21.1-1.4.0-Beta.jar - Minecraft 1.21.1 / NeoForge, commit 002b299
• instantworldmirror-1.20.1-1.4.0-Beta.jar - Minecraft 1.20.1 / Forge, commit 09fbe9c

Delete every previous Instant World Mirror JAR before installing the file matching the Minecraft version.

Validation

• Minecraft 1.21.1 GameTest: 54/54 passed
• Minecraft 1.20.1 GameTest: 51/51 passed
• Real-client menu and localization gates passed in English and Simplified Chinese on both versions.
• Full builds, JAR-content verification, configuration migration checks, and lifecycle coverage passed on both versions.
• GitHub Actions passed on both release commits.
• Team testing confirmed the Stranded Mirror and Superflat workflows without remaining issues.

Beta limitation

• Persistent mirror records currently share eight server-wide persistent world slots. Configurable per-player quotas and expanded single-player capacity are planned separately.

SHA-256

• 1.21.1: BBDDDB47BB77440B1E4EC0DF5DF754536832266E83A18441274B61740B83C25E
• 1.20.1: 908FE143914B83700A6D98C7E28BED036ED9C7FA3241BA844AF0E4627A9A3A33