Changelog

Version: 3.1.68
Date: 2026-09-10
  Retired Imported Early-Machine Set:
    - Permanently removed the unused imported early-machine set, including all three items, entities, recipes, data-stage definitions, final-fixes compatibility code, Starter Pack entries, English/Russian locale entries, icons, animations, shadows, lights and glow graphics.
    - No replacement items, recipes, settings, hidden compatibility prototypes or migration aliases were added. The removed content is no longer present anywhere in the mod package.
  Scope Safety:
    - Preserved every remaining Starter Pack item and quantity. Shelter Defense, Train Interiors, cave generation, enemies, research, power, rewards, settings and every unrelated system remain unchanged from 3.1.67.

Version: 3.1.67
Date: 2026-09-10
  Original Shelter Exterior Artwork:
    - Replaced the former shelter-k2 exterior building artwork with a new original armored cave-bunker design created specifically for The Cave.
    - Added matching original high-resolution and standard-resolution world sprites, separate shadow and warning-light layers, a 64x64 inventory/shortcut icon and a 256x256 Shelter Attack Distance technology icon.
    - Removed the unused former Shelter reflection and remnant artwork from the package. The existing GPL-3.0 open/close sounds and their licence notice remain unchanged.
  Scope Safety:
    - Kept the Shelter's 6x6 placement footprint, collision and selection boxes, health, inventory, placement rules, interior geometry, entry/exit, power, transfers, research, Wave Defense and every runtime algorithm unchanged from 3.1.66.

Version: 3.1.66
Date: 2026-09-10
  Reward Safety:
    - With Train Interiors active, Locomotives, Cargo Wagons, Fluid Wagons and Artillery Wagons are excluded from every The Cave reward selector without affecting discoverable world trains or player-owned rolling stock.
    - Existing unopened 3.1.65 Fortified Vault caches are deterministically rebuilt with the new reward policy when the save upgrades.
  Fortified Underground Vault:
    - Reduced every curated belt bundle from 500 belts, 100 underground belts and 50 splitters to 100, 20 and 10 respectively without changing its selection algorithm or tier mapping.
    - Every mixed stronghold now guarantees ten Small TNT Boxes across its blue caches, ten Medium TNT Boxes across its yellow caches and ten Large TNT Boxes across its red caches when those item prototypes are available.

Version: 3.1.65
Date: 2026-09-09
  Biter Expansion Objective:
    - Removed the visible red 200-tile Train/Shelter boundary while preserving its invisible objective aggro and nest-exclusion logic.
  Hoard Rooms:
    - Hoard Rooms now contain exactly 14 Steel Chests. Every chest makes exactly eight independent random reward picks and every basic pick quantity is doubled.
    - Doubled every guaranteed room-wide Hoard bundle without changing the room geometry, enemies or occurrence rules.
  Arachnid Queen:
    - Raised Queen health to 100,000 in Easy/Medium, 150,000 in Hard and 200,000 in Nightmare. The 30-second regeneration delay and 0.5% maximum-health-per-second rate are unchanged.
  Fortified Underground Vault:
    - Replaced 120 single-colour strongholds with 40 mixed strongholds. Each group contains 18 blue, 12 yellow and 6 red caches.
    - Each Medium/Hard/Nightmare group now has 40/50/60 mobile defenders, 3/5/7 spawners, 3/4/5 worms, 3/4/6 Gun Turrets and 2/3/5 Laser Turrets.
    - Removed cache unlock timers. The first click spawns 3/4/5 tracked mobile defenders for blue/yellow/red; after those defenders die, a second click claims the reward. Cache alarms no longer create an extra turret.
    - Replaced research-gated global loot caps with prototype-gated curated rewards and independent per-stronghold guarantees. Unresearched rewards remain eligible.
    - Every mixed group guarantees 100 level-1 modules, 50 level-2 modules, 30 level-3 modules, one Modular Armor, one Power Armor, one Power Armor MK2, 50 Gun Turrets, 1,000 Firearm Magazines, 20 Laser Turrets, one Nuclear Reactor and 300 Uranium Rounds Magazines.
    - Added large tiered belt bundles and valuable nuclear, combat, production, vehicle and equipment rewards. Turbo rewards appear only when their prototypes exist.

Version: 3.1.64
Date: 2026-09-09
  Independent Enemy Systems:
    - Wave Defense and Biter Expansion now obey their own Startup settings independently. Enabling both runs both systems together; Wave timing, routes, counts, bosses and rewards remain unchanged.
    - Replaced the unfiltered native Cave expansion dispatch with explicit real settler groups. Wave units, active Arachnid Queens and enemies already committed to an objective are never recruited, no extra enemies are spawned, and failed migration groups are safely disbanded.
  Train and Shelter Objective Aggro:
    - With Biter Expansion enabled, the live Main Locomotive or fixed Cave Shelter now has a force-local 200-tile attack radius. Ordinary mobile enemies that enter it permanently abandon migration or nest founding and attack that objective.
    - New Biter Expansion nest destinations inside the objective radius are rejected; expansion remains free to found nests outside it.
    - Added a permanently visible red, unfilled 400-tile-diameter boundary with a 6-pixel outline. It follows the Main Locomotive continuously, stays fixed on the Shelter and does not depend on ALT mode.
    - Wave Defense units and the active Arachnid Queen are excluded from the new objective controller. Existing Train and Shelter destruction/reset behaviour is unchanged.

Version: 3.1.62
Date: 2026-09-06
  Shortcut Bar:
    - Added a Gun Turret shortcut using Factorio's existing Gun Turret icon. Clicking it directly runs the same nearby 20x20 reload used by Ctrl+R without changing Inserter controls, ammunition selection or reload limits.
    - Added a corpse-cleaner shortcut using Factorio's existing Behemoth Biter icon. Clicking it runs the same per-player nearby cleanup used by Backspace and preserves permanent player corpses, live enemies, items and buildings.
    - Kept Ctrl+R and Backspace available and linked both shortcut tooltips to their existing configurable key bindings.

Version: 3.1.61
Date: 2026-09-06
  Teleporter Access:
    - Added a Teleporter button to Factorio's shortcut bar using the existing Teleporter artwork.
    - Added Ctrl+T to open or close the same existing Teleporter waypoint window for each player.
    - Removed the former 80x80 Teleporter button below Cave Information, including cleanup for upgraded saves.
    - Kept all Teleporter research, destination slots, costs, cooldowns and saved waypoint data unchanged.

Version: 3.1.60
Date: 2026-09-06
  TNT Box Progression:
    - Replaced the shared TNT Box research with a three-stage chain. Small follows Military Science Pack and costs 100 Automation, Logistic and Military packs; Medium follows Small and costs 300 of each; Large follows Medium and costs 600 of each.
    - Each research unlocks only its matching TNT Box and all three technologies reuse the same existing 256x256 research icon without duplicate graphics.
    - Moved all three TNT Box items from Logistics to a dedicated Combat row immediately below the turret row, ordered Small, Medium and Large.
    - All three recipes now require 30 base crafting seconds and use Advanced Crafting, preventing player handcrafting while allowing Assembling Machines.
  Graphics:
    - Kept the angled TNT Box artwork and added a stronger contact and lower-right cast shadow to all three world sprites.

Version: 3.1.59
Date: 2026-09-06
  TNT Boxes:
    - Added one TNT Box research after Explosives. Its base cost is 100 Automation, Logistic and Military science packs at 30 seconds per unit; The Cave's Research Level Difficulty scales it normally.
    - The research unlocks Small, Medium and Large 2x2 TNT Boxes. Recipes use one Iron Chest plus 15, 30 or 60 Explosives, craft in one second and stack to five.
    - Player-placed boxes show a ten-second world countdown and detonate automatically. Mining a box before zero safely recovers it; placing it again starts a new ten-second timer.
    - Circular blast diameters are 20, 30 and 40 tiles. Blasts remove only diggy-rock and diggy-rubble, give no direct mining items, preserve resources and run The Cave's normal Dig outcomes for enemies, rooms and special caves.
    - TNT explosions deal no scripted damage to players, enemies, buildings or resource entities. The boxes themselves are indestructible, non-military targets and cannot be blueprinted or deconstructed by construction robots.
    - A maximum of five TNT Boxes may be active globally. A sixth player placement is cancelled and the same-quality item is returned, or safely spilled beside the player if the inventory is full.
    - Added a Startup TNT Boxes Enable/Disable option, enabled by default. The complete feature is unavailable whenever Cave Collapse or Advancing Collapse is enabled.
  Graphics:
    - Added distinct yellow, orange and red 2x2 world sprites, separate shadows and 64x64 inventory icons with one, two and three visible dynamite bundles.
    - Added a dedicated transparent 256x256 TNT Box research icon.

Version: 3.1.58
Date: 2026-09-05
  Portable Filled Storage Tanks:
    - Mining a non-empty vanilla Storage Tank now creates a tagged portable tank that preserves the exact fluid type, amount, temperature, original capacity and entity quality.
    - Filled portable tanks have stack size 1 and fixed 50 kg weight, limiting a one-ton rocket to 20 tanks. Empty vanilla Storage Tanks remain unchanged at their normal 50-tank rocket capacity.
    - Player, construction-robot and Space Platform mining and placement are supported. Placement restores a real vanilla tank and its contents; failures return the tagged item to the player, robot or platform hub.
    - Only the vanilla Storage Tank is portable. The Cave's 1x1, 2x2, 3x4, 5x5 and hidden Train fluid-transfer tanks remain unchanged.

Version: 3.1.57
Date: 2026-09-02
  Arachnid Queen Boundaries:
    - Added a fixed 200-tile Queen exclusion radius around the original game start. Queens cannot spawn, select destinations, travel, excavate or place nests inside it.
    - With Train Interiors enabled, the exclusion radius is anchored once to the first starter train placement and never follows the moving train.
  Arachnid Queen Nest Cap:
    - Each Queen now counts Biter, Spitter, Snapper and Arachnid spawners in her own depth zone and pauses movement, excavation and nesting at 25 total nests.
    - A final batch creates only the remaining capacity, so 22, 23 and 24 nests become exactly 25 without overshooting. Destroying nests below the cap lets the Queen resume; regeneration remains active while paused.
    - Ordinary Nest Rooms, direct-dig settlers, Worm maturation and the Cave expansion adapter remain unchanged and are not restricted by the Queen-only cap.

Version: 3.1.56
Date: 2026-09-02
  Arachnid Queen Excavation:
    - When no opened room has space for all three nests, an active Queen now selects a safe Cave-frontier rock in her own depth zone and excavates until a suitable room becomes available.
    - Queen strikes deal double damage only to diggy-rock and diggy-rubble cover. Player characters, buildings, other enemies and ordinary combat damage are unchanged.
    - A frontier rock directly destroyed by a registered Queen now resolves the same deterministic terrain, tunnel, room, resource, special-cave, threat and direct-dig systems as a player-mined rock, without granting inventory mining yield.
    - Queen levels 1-3 no longer apply their legacy area-damage pulse while clearing an obstacle, preventing one strike from resolving several adjacent frontier rocks.
  Startup Control:
    - Added an Arachnid Queen Startup option, Enabled by default. Disabled prevents Queen spawning and removes existing Queens while preserving every ordinary three-spawner Nest Room and unrelated enemy system.
  Scope Safety:
    - The one-living-Queen-per-depth-zone cap, 30-second regeneration delay, five-minute nesting rest, exactly three weighted nests and all non-Queen enemy behaviour remain unchanged.

Version: 3.1.55
Date: 2026-09-02
  Arachnid Queen Position Fix:
    - Fixed a non-recoverable distance calculation error when a dedicated Arachnid room supplied its centre in array-form MapPosition coordinates.
    - Existing Queens affected by 3.1.54 now repair their saved current-site position from their live entity position before selecting a destination.

Version: 3.1.54
Date: 2026-09-02
  Arachnid Queen Movement:
    - All successfully opened cavern rooms are now recorded as Queen destinations, including Nauvis rooms that were previously omitted and left Easy-zone Queens stationary.
    - Queen regeneration now begins after 30 seconds without damage instead of 60 seconds; the 0.5% maximum health per second rate is unchanged.

Version: 3.1.53
Date: 2026-09-02
  Arachnid Queen Fix:
    - Fixed a non-recoverable on_tick error caused by reading Queen maximum health from LuaEntityPrototype instead of LuaEntity.
    - Applied the same API correction to legacy Queen tier migration while preserving health percentage.

Version: 3.1.52
Date: 2026-09-02
  Direct-Dig Enemy Ecology:
    - Kept the existing 3-4 ordinary-dig interval and changed its outcome to five equal 20% families: Biter, Spitter, Snapper, Arachnid or evolution-matched Worm.
    - When Allow Biter Expansion is active, surviving Biter, Spitter, Snapper and Arachnid ambushers retain normal combat distractions while travelling to found one same-family nest on valid opened Cave floor.
    - With Allow Biter Expansion active, direct-dig Worms attack normally and, if still alive after one minute, transform into one nest with Biter 20%, Spitter 20%, Snapper 30% and Arachnid 30% weights. Ordinary room Worms are unaffected.
  Family Nest Expansion:
    - Cave migrations now preserve the nearest source nest family for Biter, Spitter, Snapper and Arachnid nests while retaining native settler movement, group size, cadence, distance, placement and player-building avoidance.
    - Snapper and Arachnid nests remain script-placed only and receive no autoplace.
  Arachnid Queen:
    - The first eligible ordinary or Arachnid Nest Room can release one living Queen per Easy, Medium, Hard and Nightmare zone on each main Cave surface.
    - A dead Queen can be replaced only by the next eligible Nest Room in her original zone; Queen-laid nests never create Queens.
    - Queens are passive and non-retaliating. They travel to another valid opened room, lay exactly three independently weighted nests (20% Biter, 20% Spitter, 30% Snapper, 30% Arachnid), wait five minutes and repeat.
    - Queen health remains 10,000 in Easy/Medium, 15,000 in Hard and 20,000 in Nightmare.
    - After 60 seconds without damage, Queens regenerate 0.5% maximum health per second; new damage stops regeneration and restarts the delay.
  Save Migration:
    - Existing Arachnid bosses are adopted as Queens, legacy levels 4-10 are reduced to the correct zone tier, and duplicate same-zone bosses are consolidated to the one-Queen cap.

Version: 3.1.51
Date: 2026-09-01
  Arachnid Boss Balance:
    - Arachnid Nest rooms now use fixed bosses: level 1 in Easy and Medium, level 2 in Hard and level 3 in Nightmare.
    - Boss health is now 10,000 for level 1, 15,000 for level 2 and 20,000 for level 3.
  Scope:
    - No Market, room frequency, spawner, direct-dig ambush or unrelated gameplay behaviour changed from 3.1.50.

Version: 3.1.50
Date: 2026-09-01
  Integrated Arachnids:
    - Bundled the MIT-licensed Arachnids_enemy 1.2.0 units, spawner, bosses, graphics and sounds directly into The Cave.
    - Added dedicated Arachnid Nest rooms from depth 100 with three Arachnid spawners and one deterministic zone-scaled boss.
    - Arachnid bosses are level 1 in Easy, 2-3 in Medium, 4-7 in Hard and 8-10 in Nightmare depth zones.
    - Dedicated Arachnid rooms contain no vanilla, Armoured or regional enemies and cannot be selected back-to-back with another combat room.
    - Direct digging now completes an ambush interval every 3-4 ordinary digs and equally selects a Biter, Spitter or evolution-matched Arachnid family.
  Compatibility:
    - Added explicit conflicts with the standalone Arachnids_enemy, ArachnidsFaction and Arachnids mods to prevent duplicate prototypes.
    - Preserved existing peaceful depth, room-open suppression, local active-enemy caps and timed-cave pack behaviour.

Version: 3.1.49
Date: 2026-08-30
  Changes:
    - Train Interiors and Shelter Defense now enter or leave on the first Ctrl+Enter press.
    - Removed the remaining second-press confirmation state and updated the related English and Russian prompts.

Version: 3.1.47
Date: 2026-08-30
  Changes:
    - Industrial Loaders now have one independent item filter for each belt lane.
    - Bulk Inserter costs 100 Automation and Logistic science packs; Inserter Capacity Bonus levels 1-7 cost 250 each, with 30-second research time.
    - Stack Inserter and all 18 Transport Belt Capacity levels cost 300 Automation, Logistic and Chemical science packs, with 60-second research time.

Version: 3.1.46
Date: 2026-08-27
  Changes:
    - Entering and leaving Train Interiors now needs one Ctrl+Enter press.
    - Train Battery charging speed now rises from 50 MW to 1000 MW over 20 levels.

Version: 3.1.45
Date: 2026-08-27
  Changes:
    - Entering Train Interiors now needs one Ctrl+Enter press.
    - Main Train Expansion now has 20 research levels.
    - Train Battery Upgrade now has 20 research levels and more capacity.
    - Construction robots no longer try to repair Train Interiors rolling stock.

Version: 3.1.44
Date: 2026-08-25
  Startup Attack-Mode Load Fix:
    - Fixed the non-recoverable error raised by 3.1.43 during on_configuration_changed.
    - The Wave Defense Startup gate is now captured from game_settings during initial control.lua parsing instead of calling require from a runtime event.
    - Kept the stable 3.1.31 Wave controller within Lua's 200-local limit without adding any runtime module loading.
  Scope:
    - No Wave, Boss, queue, tunnel, Biter Expansion, pollution, balance or Startup-setting behaviour changed from 3.1.43.

Version: 3.1.43
Date: 2026-08-25
  Separate Enemy Attack Modes:
    - Added Startup options Allow Wave Defense and Allow Biter Expansion.
    - Wave Defense is Enabled by default and Biter Expansion is Disabled by default.
    - Exactly one system may run: enabling both activates neither and displays a clear conflict warning; disabling both leaves Train Interiors or Shelter Defense active without either attack system.
  Stable Wave Defense Rollback:
    - Restored the complete Train/Shelter Wave controller and Wave-unit prototypes from the player-confirmed stable 3.1.31 implementation.
    - Removed the 3.1.40-3.1.42 Unit Group interception, AI overrides, Boss detachment migration and global on_unit_added_to_group hook.
    - Wave timing, queues, tunnels, Bosses, military diversion, blocker recovery, rewards and balance now follow the stable 3.1.31 controller.
  Preserved Biter Expansion:
    - Kept the current dense zero-spacing placement, Evolution-scaled 10-to-2-minute cadence, native migration, target scoring and settler rules unchanged when Allow Biter Expansion is selected.
    - Its 0.1 pollution attack cost and one-percent spawner absorption now apply only in Biter Expansion mode, preventing those global modifiers from leaking into Wave Defense.
    - The former runtime Map switch remains hidden only for save compatibility; the new Startup selector is authoritative.
  Scope:
    - Preserved current interior pollution venting, Train/Shelter power fixes, item/fluid transfer, Cave generation and every unrelated 3.1.42 system.

Version: 3.1.42
Date: 2026-08-25
  Boss Unit Group Detachment:
    - Replaced the previous command-only Boss recovery with real Unit Group detachment.
    - A recruited Boss is moved alone through a temporary script group which is immediately destroyed, unlinking the Boss without killing or modifying any native nest units.
    - The exact tunnel, blocker, Main Locomotive or Shelter command is restored only after the Boss is no longer a member of the native group.
  Existing Save Recovery:
    - Increased the Wave AI isolation migration version so a Boss already stranded beside a nest in a 3.1.41 save is detached and resumed in place on the first normal update.
  Scope:
    - Kept native enemy groups, nest units, pollution, Wave balance, Boss health, damage, timing, tunnels and blocker recovery unchanged.

Version: 3.1.41
Date: 2026-08-25
  Boss Wave Group Isolation:
    - Added a dedicated once-per-second Boss guard that detects both real native-group membership and a replaced Factorio group command.
    - A diverted Boss now immediately receives its exact current tunnel, obstacle, Main Locomotive or Shelter command again instead of gathering beside a Cave nest.
    - Increased the Wave AI isolation migration version so a Boss already active in an existing 3.1.40 save is recovered in place on the first normal update.
  Scope:
    - Kept Boss health, damage, obstacle attacks, two-minute blocker recovery, Wave counts, queues, tunnels and timing unchanged.
    - Native nest units, pollution attacks, enemy expansion and ordinary Wave attackers remain unchanged from 3.1.40.

Version: 3.1.40
Date: 2026-08-25
  Train Wave Attacker Isolation:
    - Prevented scheduled Train and Shelter Wave Biters, Spitters and Bosses from joining native enemy attack groups created by nearby spawners.
    - Wave attackers can no longer abandon their scripted tunnel, player, military-target or Main Locomotive/Shelter route to gather beside a Cave nest or return to a spawner.
    - Kept every Wave attacker on the normal enemy Force, preserving turret hostility, combat rewards, Evolution tiers, military diversion and compatible enemy interactions.
  Existing Save Recovery:
    - Existing registered Wave attackers are isolated in place and receive their correct current command again without being killed, teleported or counted as a new spawn.
    - An event-driven guard immediately restores any Wave attacker that another system attempts to add to a native unit group; no map-wide or per-tick enemy scan was added.
    - Existing active counts, queued attackers, Boss progress, tunnels, Wave timers and the current save remain intact.
  Scope:
    - Native nest Biters, Spitters, expansion groups, pollution attacks, nest density, Wave population, active-enemy caps and every unrelated system remain unchanged from 3.1.39.

Version: 3.1.39
Date: 2026-08-25
  Minimal Enemy-Spawner Pollution Absorption:
    - Reduced the direct industrial-pollution absorption rate of every loaded unit-spawner prototype to one percent of its existing value.
    - Vanilla Biter, Spitter and integrated Armoured Biter spawners therefore change from absolute 20 / proportional 0.01 to absolute 0.2 / proportional 0.0001.
    - Compatible modded spawners with their own pollution absorption retain their relative balance and are scaled by the same one-percent multiplier instead of relying on a hard-coded name list.
  Attacks and Pollution Spread:
    - Kept the enemy attack pollution consumption modifier at 0.1. Pollution-triggered attackers remain ten times cheaper than vanilla while each nest removes pollution from its chunk one hundred times more slowly.
    - Dense zero-spacing nest clusters can still collect real pollution and launch native Factorio attacks, but should no longer act as an immediate pollution wall before the cloud can reach nests farther along opened Cave routes.
    - Absorption remains finite rather than being disabled. Spores and every non-industrial airborne pollutant retain their loaded prototype values.
  Existing Saves and Scope:
    - Existing saves adopt the prototype change automatically after loading this version; pollution already absorbed by nests cannot be restored.
    - Five-times Train/Garden/Shelter venting, exterior pollution already left behind, tile/tree/void absorption, diffusion, Evolution, zero-spacing Enemy Expansion and every unrelated system remain unchanged from 3.1.38.

Version: 3.1.38
Date: 2026-08-25
  Minimum Pollution Attack Cost:
    - Reduced Factorio's enemy attack pollution consumption modifier from 0.5 to 0.1, the minimum supported value.
    - A pollution-triggered enemy now costs one tenth of the normal pollution amount, allowing the same real pollution to fund approximately ten times the normal number of attackers before ordinary group timing and population limits are applied.
    - Dense front-line nests need only one fifth of the pollution required in 3.1.37 to fund equivalent attack groups, giving substantially more of the cloud a chance to continue toward deeper nests.
  Existing Saves and Scope:
    - New games receive the 0.1 attack-cost modifier during initialization. Existing saves adopt it automatically when loading this version.
    - Pollution production, five-times interior venting, diffusion, tile/tree/void absorption, zero-spacing Enemy Expansion and every unrelated system remain unchanged from 3.1.37.

Version: 3.1.37
Date: 2026-08-25
  Lower Pollution Attack Cost:
    - Set Factorio's enemy attack pollution consumption modifier from 1.0 to 0.5.
    - Each pollution-triggered enemy now needs half the previous pollution to join an attack group, so the same real pollution can fund approximately twice as many attackers before ordinary group timing and population limits are applied.
    - Dense front-line nests require less total absorbed pollution to fund their attacks, giving the remaining cloud more opportunity to continue toward nests deeper inside opened Cave routes.
  Existing Saves:
    - New games receive the 0.5 attack-cost modifier during initialization. Existing saves adopt it automatically when loading this version.
  Preserved Pollution and Enemy Behaviour:
    - Five-times Train/Garden/Shelter pollution venting, diffusion, the 15-pollution spread threshold, tile/tree/void absorption, Evolution and exterior machine pollution remain unchanged.
    - Dense zero-spacing Enemy Expansion, its 10-to-2-minute cadence, maximum reach, settler group size, native migration and every unrelated enemy system remain unchanged from 3.1.36.

Version: 3.1.36
Date: 2026-08-25
  Dense Enemy Expansion:
    - Removed the three-chunk minimum spacing from Cave enemy expansion. On Factorio versions that expose min_expansion_distance, The Cave now keeps it at zero while its Enemy Expansion setting is enabled.
    - Removed all existing-enemy-base influence from The Cave's expansion target score. Open chunks beside an existing nest and chunks already containing nests remain eligible for further expansion.
    - Expansion can now densify opened Cave floor until normal entity collision leaves no valid location for another spawner. Existing nests are not moved, deleted or regenerated.
  Preserved Expansion Rules:
    - Player-building influence, maximum expansion reach, Evolution-scaled 10-to-2-minute cadence, settler group size and Factorio's native migration/base construction remain unchanged.
    - Natural cavern generation, Gleba nest generation, Direct-dig enemies, pollution, Wave Defense and every unrelated system remain unchanged from 3.1.35.
  Existing Saves and Testing:
    - Existing saves adopt the zero-spacing rule automatically after loading this version. /the-cave-expansion-test 100 can still be used to test the established two-minute maximum-Evolution cadence.

Version: 3.1.35
Date: 2026-08-25
  Five-Times Interior Pollution Venting:
    - Train Interiors, the Locomotive Garden and Shelter Defense now vent exactly five times the real pollution collected from their factory-capable interior surfaces.
    - One unit collected inside therefore adds five units at the current exterior Main Locomotive or fixed Shelter position. An idle interior still adds zero pollution; no fixed or time-based source was introduced.
    - Efficiency Modules and machine activity continue to determine the real source amount before the 5x multiplier is applied.
  Minimal Cave-Void Absorption:
    - Reduced the industrial-pollution absorption of Factorio's out-of-map tile to 0.000001 per tile per second, exactly one percent of its vanilla value.
    - A completely void-filled 32x32 chunk now absorbs only 0.06144 pollution per minute instead of 6.144. The leak remains finite rather than being disabled entirely.
    - Existing saves adopt the prototype change automatically. Already absorbed pollution is not recreated; newly produced pollution persists and spreads under the reduced void loss after loading this version.
  Preserved Pollution Behaviour:
    - Normal floor and tree absorption, enemy-spawner consumption, diffusion, map pollution settings and ordinary exterior machine emissions remain unchanged.
    - Only the standard pollution entry on out-of-map is changed. Spores and other airborne pollutants retain their loaded values.
    - Pollution emitted at previous train positions is never cleared, moved or reassigned by The Cave.
  Testing:
    - /the-cave-pollution-test reports the real amount collected inside, the 5x amount vented outside and the active multiplier separately.
  Scope Safety:
    - Interior power, Train and Shelter batteries, item/fluid transfer, Wave Defense, enemy AI and every unrelated system remain unchanged from 3.1.34.

Version: 3.1.34
Date: 2026-08-25
  Triple Interior Pollution Venting:
    - Train Interiors, the Locomotive Garden and Shelter Defense now vent exactly three times the real pollution collected from their factory-capable interior surfaces.
    - One unit collected inside therefore adds three units at the current exterior Main Locomotive or fixed Shelter position. An idle interior still adds zero pollution; no fixed or time-based source was introduced.
    - Efficiency Modules and machine activity continue to determine the real source amount before the 3x multiplier is applied.
  Exterior Behaviour:
    - Pollution emitted at previous train positions is never cleared, moved or reassigned. New emissions follow the train and add to any pollution still present when it revisits an area.
    - Factorio remains responsible for normal exterior diffusion, terrain and tree absorption, spawner consumption and enemy attacks. Ordinary exterior miners, assemblers and other pollution sources are unchanged.
  Testing:
    - Updated /the-cave-pollution-test to report the real amount collected inside, the 3x amount vented outside and the active multiplier separately.
  Scope Safety:
    - Interior power, Train and Shelter batteries, item/fluid transfer, Wave Defense, enemy AI, map pollution settings and every unrelated system remain unchanged from 3.1.33.

Version: 3.1.33
Date: 2026-08-25
  Train Garden Power Distribution:
    - Removed the accidental surface-wide global electric network from the Locomotive Garden. Garden machines now require normal electric-pole coverage instead of receiving power through the floor.
    - Replaced only the lower Garden fixture with a dedicated wire-connector Substation. Its 36-tile copper-wire reach is retained, but its direct supply area is limited to its own protected 2x2 footprint.
    - Kept the existing native scripted copper connection from the Main Locomotive Substation to the lower Garden connector. The Main Locomotive Substation keeps its established 36x36 coverage unchanged.
  Shelter Defense Power Distribution:
    - Reduced the fixed Shelter Main Substation direct supply area from 36x36 to its own protected 2x2 footprint, so normal Shelter machines require player-built electric poles.
    - Kept the hidden one-way Shelter Battery charger beneath the fixed connector, its 36-tile wire reach, battery capacities, charge/discharge rates and exterior emergency output unchanged.
    - Shelter interior surfaces now defensively remove a global electric network if an old, editor-modified or externally modified save enabled one.
  Existing Save Migration:
    - Existing Garden global networks are removed automatically when the mod configuration updates.
    - Existing lower Garden Substations are replaced in place while preserving their live copper-wire neighbours; the cross-surface power link is then verified and repaired by the existing 15-tick infrastructure sync.
  Scope Safety:
    - Train Battery isolation, Shelter Battery isolation, exterior accumulators, generators, pollution venting, item/fluid transfer, room geometry, Wave Defense and every unrelated power bridge remain unchanged.

Version: 3.1.32
Date: 2026-08-25
  Real Interior Pollution Venting:
    - Train Interiors and Shelter Defense now collect the real pollution present on their factory-capable interior surfaces every three seconds and vent exactly that amount onto the live exterior surface.
    - No fixed pollution source, minimum, multiplier, exponential growth or artificial time-based pollution was added. Efficiency Modules, machine activity and power usage therefore continue to control the resulting pollution naturally.
    - Scripted venting uses Factorio pollution rather than a separate attack counter, so the exterior cloud retains its normal diffusion, absorption, Evolution and native enemy-attack behaviour.
  Moving Train Pollution Trail:
    - A Train Interior vents at the Main Locomotive's current exterior position. Pollution already emitted at an earlier stop or along the route is never cleared, moved or reassigned when the train moves.
    - Each new position receives only newly produced interior pollution. Returning to a previously polluted area adds to the pollution still present there after Factorio's normal diffusion and absorption.
    - Coupled wagons sharing one interior surface are counted once per cycle. The Locomotive Garden vents separately through the same live Main Locomotive.
  Shelter Defense:
    - Shelter interior pollution vents at the fixed exterior Shelter position and remains there under Factorio's normal pollution simulation.
  Existing Saves and Testing:
    - Historical pollution trapped inside before this feature existed is cleared once during migration and is not dumped outside as a sudden backlog. Only pollution produced after upgrading is transferred.
    - Added /the-cave-pollution-test to report the latest Train, Train Garden and Shelter transfer amount, exterior position and transfer status.
  Scope Safety:
    - Exterior pollution is never cleared by this system. Wave Defense, enemy AI, map pollution settings, machine emissions, power bridges, item/fluid transfer and Resource Cave/Lost City/Fortified Vault surfaces remain unchanged.

Version: 3.1.31
Date: 2026-08-24
  Quality-Aware Cross-Surface Item Transfer:
    - Train Interiors Cargo Wagon import/export now tracks each item name and Quality separately and transfers Normal, Uncommon, Rare, Epic and Legendary stacks without changing their Quality.
    - Shelter Defense exterior/interior import/export now uses the same Quality-aware counting, removal, insertion and safe remainder rollback.
    - Existing version-1 transfer snapshots preserve their established Normal-item baselines while retrying only non-Normal stacks already stuck in a Cargo Wagon, Shelter exterior inventory or interior Export Storehouse.
  Audited Transfer Paths:
    - Locomotive Garden already moves complete LuaItemStack objects, preserving Quality and stack metadata.
    - Uranium/Mineral Resource Caves and Lost City already use Factorio linked belts, preserving item Quality natively; their transfer code is unchanged.
  Scope Safety:
    - Fluid transfer, power bridges, train/shelter layouts, Storehouse roles, transfer direction, Wave Defense, Cave balance and every unrelated gameplay system remain unchanged.

Version: 3.1.30
Date: 2026-08-24
  Faster Enemy Expansion:
    - Replaced the standard 60-to-4-minute Cave expansion cadence with a linear 10-to-2-minute interval: 10 minutes at 0% Evolution, 8 at 25%, 6 at 50%, 4 at 75% and 2 at 100%.
    - Each interval remains one migration attempt rather than a guaranteed nest. Existing enemy spawners, eligible opened Cave floor, Factorio's influence scoring and a successful settler migration are still required.
    - Existing saves discard only their previously scheduled long Expansion timestamp once during migration, then begin a fresh interval at their current Evolution. Pending settler migrations and all other Expansion state are preserved.
  Admin Testing:
    - Added /the-cave-expansion-test <0-100|status>. Setting a percentage updates Evolution on every main Cave surface and starts a fresh interval at that level; status reports Evolution, live enemy-spawner count, remaining time and whether expansion is enabled.
  Scope Safety:
    - Expansion distance, settler group size, target scoring, native migration/base construction, Direct-dig enemies, cavern rooms, Train/Shelter Wave Defense and every unrelated gameplay system remain unchanged.

Version: 3.1.29
Date: 2026-08-24
  Boss Blocker Combat:
    - Increased every Train/Shelter Wave Boss strike from the copied Behemoth value to 200 physical damage while retaining the established attack speed, movement speed, health scaling and resistances.
    - After deployment, a Boss now attacks only player-force entities whose collision boxes actually block its current tunnel waypoint or direct route to the Main Locomotive/Shelter. Natural Cave cover, belts, rails and unrelated nearby structures are not selected.
    - One continuous 120-second obstruction window covers an entire layered barrier. Damaging, destroying or switching between individual wall layers does not restart the timer; it clears only after the Boss has moved eight tiles beyond the last blocker.
  Boss Recovery:
    - A Boss that remains obstructed for 120 seconds is removed without a death, corpse, loot, coins or kill credit and the same logical Boss is queued through a different directional tunnel with its remaining health preserved.
    - A Boss removed by another mod without an entity-death event is recovered through the same queue instead of leaving the Boss Wave permanently stuck at Unknown.
    - Only a real Boss death advances the Boss counter and starts the established 15-minute post-Boss break.
  Shared Scope:
    - The same implementation is used by both Train Interiors Wave Defense and Shelter Defense; their separate final targets and every unrelated Wave rule remain unchanged.

Version: 3.1.28
Date: 2026-08-23
  Composable Startup Modes:
    - Removed the single-choice Game Mode dropdown and restored the established independent Startup settings for Cave Collapses, Train Interiors, Shelter Defense, CAVETORIO and Advancing Collapse at the top of Startup settings.
    - Restored Digging Mode as one dropdown with Disabled, Hardcore and Levels 1–4 instead of five separate Game Mode entries.
    - Compatible features can once again be combined, including Train Interiors with Cave Collapses, Advancing Collapse and any Digging Mode level.
    - Normal The Cave remains the baseline when the optional scenario settings are Disabled.
  Compatibility:
    - Train Interiors and Shelter Defense remain mutually exclusive. If both are Enabled, neither interior scenario starts and the established conflict warning is shown.
    - CAVETORIO retains its established requirements: CAVETORIO, Train Interiors and Everything on Nauvis Enabled, with Shelter Defense Disabled.
  Scope Safety:
    - Resource Cave balance, loot, enemies, Evolution, Train/Shelter interiors, power systems, wave rules and every unrelated gameplay system remain unchanged from 3.1.27.

Version: 3.1.27
Date: 2026-08-23
  Timed Resource Cave Enemy Pressure:
    - Removed the ten-room generation ceiling from active Iron, Copper, Coal and Uranium Caves. New rooms may continue to open until the timed cave closes.
    - Resource Cave interiors remain limited to Empty Rooms and Enemy Nest Rooms. Eligible rolls use a 40/60 Empty/Nest weighting, never permit consecutive Nest Rooms and guarantee a Nest after at most two Empty Rooms.
    - Each Nest Room retains exactly three spawners plus its existing zone-scaled worms. At most 12 enemy spawners may remain alive on one Resource Cave surface; new rooms stay empty until enough spawners have been destroyed to fit another complete Nest Room.
    - Direct player mining between rooms now creates a bounded difficulty-scaled group: 2–3 on Easy, 3–5 on Medium, 5–8 on Hard and 8–12 on Nightmare. The established nearby active-unit caps still prevent accumulated combat spikes.
  Evolution:
    - Destroying an enemy unit-spawner in one of the four Resource Caves through a player or player-owned force now applies Factorio's live spawner-destruction factor to that cave's parent surface Evolution.
    - Worms and mobile units do not add this Evolution, and scripted cave closure, cleanup, migration or surface deletion cannot award it.
    - The parent value continues to synchronize to its owned child missions. Main-surface enemies, Lost City ambushes, Fortified Vault enemies and Wave Defense tiers can therefore reflect the higher Evolution naturally; their timing, population, routing and AI logic are unchanged.
  Scope Safety:
    - Main-surface Direct-dig events remain single-enemy events. Lost City generation, Fortified Vault generation, Train Interiors, Shelter systems, Wave Defense rules, enemy identity and Damage Indicator logic remain unchanged.
    - No Resource Cave nest is regenerated behind cleared players. Replacement Nest Rooms can appear only ahead in newly opened rooms, and no separate lower-cave expansion system was added.

Version: 3.1.26
Date: 2026-08-23
  Industrial Logistic Progression:
    - Fixed Logistic Containers incorrectly unlocking every industrial logistic chest at the early 250-pack research tier.
    - Logistic Containers now unlocks only Passive Provider and Storage variants for the Industrial Container, Industrial Storebox and Industrial Storehouse.
    - Requester, Buffer and Active Provider variants for all three sizes now unlock with Factorio's native Logistic System technology.
    - The advanced variants therefore follow the active game mode automatically: Utility science in the base game and Space science in Space Age.
  Existing Saves:
    - Added a targeted migration for the nine advanced industrial logistic recipes. They remain enabled only for forces that have researched Logistic System; no unrelated recipe or technology state is reset.
  Scope Safety:
    - Container capacities, ingredients, entities, inventories, filtering, basic and dedicated Filtered variants, and every unrelated system remain unchanged.

Version: 3.1.25
Date: 2026-08-23
  Chest Filtering:
    - Added a Chest Filtering Startup dropdown with Enable and Disable choices. Enable is the default so existing saves retain the established filtering behaviour automatically.
    - Enable gives every compatible normal and logistic chest Factorio's native cargo-wagon-style slot filters, matching the previous unconditional behaviour.
    - Disable skips only The Cave's global chest conversion. Ordinary chests keep their original inventory behaviour, while the dedicated Filtered Industrial Container, Filtered Industrial Storebox and Filtered Industrial Storehouse remain filterable.
    - The existing compatibility blacklist remains unchanged. Changing this Startup setting requires a restart; disabling it on an established save can remove ordinary-chest slot-filter assignments.
  Scope Safety:
    - The implementation does not change chest capacities, contents, recipes, technologies, graphics, entity names, dedicated Filtered prototypes or unrelated systems.

Version: 3.1.24
Date: 2026-08-23
  Wave Defense Panel:
    - Fixed the +/- panel button in Shelter Defense by routing Wave UI clicks before the Train Interiors-only GUI guard.
    - New and existing Wave Defense panels now start in a compact one-row state and can be expanded or collapsed independently by each player.
    - Removed the expanded panel's forced dimensions while it is collapsed, reducing its closed footprint to the natural header size.
    - Shelter Defense now uses Shelter-specific panel titles, compact headers, paused text and tooltip; Train Interiors retains its established Train Wave wording.
  Scope Safety:
    - Wave timing, scaling, enemies, tunnels, rewards, Train Interiors, Shelter mechanics and every unrelated system remain unchanged.

Version: 3.1.23
Date: 2026-08-22
  Everything Has Quality Integration:
    - Added one Startup base-quality percentage setting with a 0–100 range and a default of 0.
    - Zero is a strict no-op. Values from 1 to 100 apply base quality to assembling machines, furnaces and mining drills.
    - When enabled, Uncommon quality is unlocked for every force and negative module quality effects are clamped to zero.
    - The official Quality mod is optional; the integrated feature safely remains inactive when Quality is unavailable.
  Compatibility:
    - Declared the standalone quality-everything mod incompatible to prevent duplicate prototype changes.
    - Integrated behaviour is based on Everything has Quality 0.0.3 by LuckyLMJ.

Version: 3.1.22
Date: 2026-08-22
  Starter Train Interior Order:
    - Kept the initial orientation lock active until the complete three-part Main Train is actually observed, including couplings completed after the initial spawn event.
    - The starter interior is fixed left-to-right as Fluid Wagon, Cargo Wagon, Locomotive, matching the established right-to-left view: Locomotive, Cargo Wagon, Fluid Wagon.
    - The lock closes permanently after that first complete set. Battery, power, fixtures, room geometry, later coupling, discovered train parts and unrelated systems are unchanged.

Version: 3.1.20
Date: 2026-08-22
  Startup Game Mode:
    - Removed the fresh-game Main Lobby and restored direct startup through Settings > Mod Settings > Startup.
    - Added one first-position Game Mode dropdown with Normal The Cave, Cave Collapses, Train Interiors, Shelter Defense, CAVETORIO, Advancing Collapse and five direct Digging variants.
    - Removed the separate scenario Enable/Disable prototypes and translated the new choice centrally to the established legacy setting interface.
  Protected Systems:
    - Train Interiors, Train Wave Defense, Shelter Defense, rolling-stock order, power systems and interior runtime files remain byte-for-byte identical to 3.1.15.
    - Cave Information and Teleporter retain their original 3.1.15 top-left placement without any screen-position code.

Version: 3.1.15
Date: 2026-08-21
  Thirty-Minute Fortified Raid:
    - Increased the shared Fortified Vault timer from 20 to 30 minutes.
    - The existing duration migration updates active Vaults to a total of 30 minutes measured from their original first-entry tick; it does not restart the raid timer.
    - Updated the outside Display Panel, mission information and all English/Russian Fortified entrance descriptions to state the new 30-minute duration.
  Scope Safety:
    - Unlimited cache openings, reward budgets, blacklist and progression filters, the 70x70 safe-zone rendering, the 10-tile enemy spawn buffer, all 120 groups and unrelated Cave systems remain unchanged.

Version: 3.1.14
Date: 2026-08-21
  Unlimited Fortified Cache Openings:
    - Removed both successful-opening limits from Fortified Vaults. Players no longer have a personal cache cap, and the raid no longer stops after a shared number of opened caches.
    - Any player may keep hacking as many of the physically generated caches as time and combat permit. Personal and raid-wide opened counts remain as information only.
    - The established Fortified reward blacklist, research and region gates, combined science ceiling, item quantity budgets, armor/equipment budgets and final-payout validation remain unchanged.
  Twenty-Minute Raid:
    - Increased the shared Fortified Vault timer from 15 to 20 minutes.
    - Existing active records migrate to a 20-minute close time measured from their original first-entry tick; the migration is idempotent and does not restart the raid.
    - Updated English and Russian entrance descriptions, mission information, Vault panel, entry message and cache-success message to remove every obsolete opening-limit claim.
  Scope Safety:
    - The 70x70 rendered safe zone, 10-tile defender spawn buffer, 120 full-size groups, 1,440 physical caches, 40,000 rocks, alarms, hack durations and unrelated Cave systems remain unchanged.

Version: 3.1.13
Date: 2026-08-21
  Fortified Vault Safe-Zone Test:
    - Expanded the newly generated lower-Vault combat-safe square from 50x50 to 70x70 while preserving the existing 700x700 floor, exact arrival pad and all 120 full-size stronghold groups.
    - Added a further 10-tile static-enemy spawn buffer outside the visible boundary. Stronghold centres shift outward and unsafe defender targets are relocated rather than intentionally reducing defender totals.
    - Added a thin green 70x70 owner-Force-only rendering outline and localized label. It is visual only: no wall, collision, enemy damage, enemy deletion, AI override or recurring area scan is introduced.
    - Existing active Vault layouts are not rewritten. Generate a new Fortified Vault to test the expanded boundary and shifted initial defender placement.
  Scope Safety:
    - Cache rewards, blacklists, research and region gates, quantity budgets, rocks, hack limits, raid timer and unrelated Cave systems remain unchanged.

Version: 3.1.12
Date: 2026-08-21
  Fortified Stronghold Density:
    - Increased newly generated Fortified Vault strongholds from 30 to 120: 40 Standard, 40 Secure and 40 High-Security groups.
    - Preserved the complete old group template instead of dividing it: cache counts and every Medium/Hard/Nightmare defender family scale fourfold with the four-times-larger 700x700 floor.
    - New Vaults contain 720 Standard, 480 Secure and 240 High-Security caches. The 10-per-player and 20-per-Vault successful-open limits remain unchanged.
  Dynamic Four-Category Rewards:
    - Replaced the narrow fixed tier pools with runtime discovery from the Logistics, Production, Intermediate Products and Combat item groups. Recipe-backed items require their recipe to be researched; physical Market-only items without recipes, including The Cave MK/Toolbelt equipment, remain eligible.
    - Selection balances the four groups before choosing individual items, so Intermediate Products cannot crowd the other categories out.
    - Added deterministic per-stronghold diversity rerolls: adjacent caches cannot reuse an identical loadout when another eligible combination exists, and the preferred overlap ceiling is 50 percent.
    - Expanded conservative quantity handling for portable equipment, turrets, combat robots, mines, artillery and dynamically discovered mod items while retaining every agreed per-Vault hard cap.
  Reward Safety and Progression:
    - The complete Fortified blacklist, whole Items > Space exclusion, combined 400 science-pack ceiling, one-armor/four-equipment ceilings and final-payout checks remain mandatory.
    - Every recipe-backed candidate still requires an enabled Force recipe. Explicit item mapping plus technology-graph inference limits planetary recipes to the matching Cave coordinate region.
    - Existing unopened caches are rebuilt deterministically through the dynamic catalog on configuration change. Existing active Vault geometry and defenders are not duplicated; spawn a new Vault to test all 120 groups.
  Scope Safety:
    - Lost Village, other cave types, recipes, technologies, enemies outside Fortified Vaults, Train systems, Shelter systems and unrelated gameplay remain unchanged.

Version: 3.1.11
Date: 2026-08-21
  Fortified Vault Scale and Access:
    - Expanded every newly generated Fortified Vault from 350x350 to 700x700 while preserving the exact 50x50 central combat-safe square and the small clear arrival pad.
    - Increased natural Vault rocks from 10,000 to 40,000 to preserve the previous floor density across the four-times-larger area.
    - Increased the successful cache limit from 6 to 10 per player and from 15 to 20 for the entire Vault. The existing first-completed, first-served behavior remains unchanged.
    - Cache totals, 30 stronghold groups, group composition, raid timer, alarms and Medium/Hard/Nightmare defender counts remain unchanged.
  Fortified Reward Safety:
    - Added a Fortified-only hard blacklist for every requested science pack, endgame material, fuel, weapon, armor, equipment and building. The entire runtime Items > Space item group is also denied automatically, including items added to that group by other mods.
    - Blacklisted items are rejected at pool selection, cache insertion, existing-cache migration and final payout. The items remain fully available everywhere outside Fortified Vault rewards.
    - Rewards now require an actually enabled owner-Force recipe. Planet-discovery auto-research alone cannot leak locked recipes, and mapped planetary rewards are limited to their matching Cave coordinate region.
    - Replaced repeated 18/24/30 picks and quantity multipliers with one deterministic bundle per selected item type. Jackpot bundles obey the same blacklist, research, region, tier and quantity rules.
  Shared Reward Budgets:
    - Added the agreed per-Vault hard ceilings for materials, circuits, belts, underground belts, splitters, robots, machines, ammunition, modules, armor and equipment across every cache and every player.
    - Whitelisted science packs share one combined 400-pack ceiling per Vault. When several types compete for the remaining science budget, it is divided evenly and unused shares are redistributed.
    - A Vault can award at most one armor item and four wearable equipment items in total. Armor, equipment, tier-3 modules, nuclear reactors and railgun ammunition are High-Security-only.
  Existing Saves and Scope Safety:
    - Existing active Vault records receive the new reward budgets and every still-unopened cache is deterministically rebuilt through the new filters on configuration change.
    - Already generated 350x350 child surfaces keep their existing geometry until that short-lived raid closes; the next generated Vault uses 700x700 and 40,000 rocks.
    - Lost Village, other cave types, recipes, technologies, enemies, Train systems, Shelter systems and unrelated gameplay remain unchanged.