Engine changelog

Release notes for the engine crate (engine-rs/Cargo.toml), one ## <version> section per crate version, newest first, written for people who build on the engine. The player-facing notes live in CHANGELOG.md, one section per app version. A crate bump adds its section here in the same PR (src/tests/engineChangelog.guard.test.ts enforces it). Describe what changed in the engine’s contract and behavior: saves, frame and view layouts, the catalog, identity, the binding, and rules. An engine change a player can feel also gets a line in the app changelog.

Entries up to 0.24.0 were written afterward from the history of the commits that raised the version, so they are documentation only.

There is no entry for 0.17.0, which only existed as a step inside a stacked branch.

1.25.0 (2026-11-11)

• remove_facility on a sold condo charges the household’s buy-back price (household_price of its sale price) before the resale refund, refuses when the money cannot cover it, and logs the buy-back; unsold and gutted condos are unchanged.
• New economy::visitors module: each venue’s expected visitors are set at the daily rollover from yesterday’s served count and a climb of 1 to 3 steps of 5, rolled from the tower’s founding seed, the day and the room, so the main RNG stream is untouched. census_count for shops, fast food and restaurants returns Unit::visitors_yest (saved as visitorsYest), the star census no longer subtracts hotel guests from them, and a gutted venue clears it. The conformance lock moves on every scenario.
• The TDT importer reads each floor’s remap and each retail row’s byte 8 to seed visitorsYest; TdtTower gains TdtFloor::index_map and TdtTail::retail.
• economy::visitors gains the set audience: set_audience, counts_set_audience and census_follows_the_day. census_count for party halls and cinemas returns Unit::visitors_yest, which the daily rollover sets to the audience on a room’s first night open (a cinema keeps the count it has), and the save loader keeps it for those kinds. The conformance lock moves.
• TdtTenant gains draw (byte 15, a theatre’s film draw). The TDT importer seeds party halls and theatres from it when a class adds up to the finance line, or with an even share when the line splits into a valid audience.
• economy::visitors gains film_draw and the aging constants. Extras gains film_days (saved as filmDays, cinemas only); the daily rollover counts a cinema at the draw of its film’s age and then ages the film. A gutted cinema starts a new film. The conformance lock moves; the ransom-declined-classic scenario’s threat now comes at hour 352.
• tdt::venues reads and writes the original’s party hall and theatre table (read_venue_table, write_routing_tail), and TdtTail gains venues. The importer seeds each theatre’s filmDays from it. The exporter writes byte 15 (the film’s draw), the table, and an index map from logical unit id to tenant; every TDT export hash moves.
• Simulation::change_film(id, classic) and the port command changeFilm(id, classic) (a cost slot; refusals unavailable, notTheater, closed and funds) change a Classic theatre’s film. GameMode::film_changes gives the prices, and the catalog adds newFilmPrice and classicFilmPrice (null in Modern); CATALOG_VERSION is 8.
• Extras gains film_classic (saved as filmClassic, cinemas only), and visitors::showing_draw holds a classic’s draw to 1. Classic’s pay_maintenance books no films, and its blockbusters are the theatres whose film draws a full house, set at the morning rollover, on a change and when a theater opens. Modern’s booking resets the film after the day’s rollover has counted the spent one (pay_maintenance now answers the booked theatres, and start_booked_films opens their films). The conformance lock moves.
• unitCard adds the filmDays and filmClassic slots, and the frame layout’s VIEW_LAYOUT_VERSION is 14.
• The TDT importer reads a film number below 6 as a classic and the exporter writes film 3 for one (venues::is_classic_film, TdtVenue::shows_classic).
• Modern: the unmet-demand coverage adds the daily income capacity of reachable attendance venues to the retail capacity; the income share still reads retail only, and Classic is unchanged (#705).
• The binding gains tooling members for the screenshot and test harnesses: bare placements (placeBare, placeTransportBare) and reads of a unit, a shaft, a tile, a floor’s lobby and service, and the highest floor. No game command reaches them.

1.24.0 (2026-11-11)

• A declined ransom starts a timed bomb search in both modes (a hidden bomb, guards sweeping floors from the emergency stairs, a deadline) that the save keeps as events.bomb while it runs; Classic still calls only on a tower with Security.
• bombSearch() reads the search (each guard’s floor, rooms, start, arrival and finish), and the view’s header adds bombSearchSeq (view layout 13).
• New gameplay event bomb_found; the web build reports bomb_outcome (paid, found or exploded).

1.23.0 (2026-11-10)

• The binding drops towerSetCars and towerResizeTransport, the silent tower edits only the retired dual-run mirror called; setCars and resizeTransport stay for uncharged edits.

1.22.1 (2026-11-10)

• The tooling-only WASM binding gains vacateUnit(id, reason) and setUnitRent(id, rent). vacateUnit runs the churn pass’s departure on a chosen room for a named cause, buying back a sold condo, outside any open undo step. setUnitRent writes a room’s price as given, with no ladder snap or band clamp, or clears it with null. Each refuses an unknown unit, an unknown cause, or a price that is not finite or is below 0, and changes nothing then. The TypeScript reference exposes the same test hooks, so the last write-only tests (condo re-listing and price stamping, and the HUD’s kept room counts) run on both engines.
• No saved-game, frame, view-layout or catalog format changes. The public binding interface digest moves.

1.22.0 (2026-11-10)

• A lobby tile placed where there is no floor yet pays the floor’s price on top of the lobby’s, as the original charges a $500 floor tile with each $5,000 lobby tile placed where there is no floor yet. This covers a lobby placement, the Floor tool on the ground floor (which lays a lobby) and every gap tile a lobby bridge fills, so quoteBuild and canBuild quote, and buildAt, build, paintTiles and paintBrush charge, $5,500 for each such tile. A lobby placed over a floor tile still pays the lobby’s price alone.
• The catalog publishes the rule: each facility entry gains paysForFloor, true for the lobby alone, and CATALOG_VERSION is 7. The prices are unchanged.
• resizeTransport refuses an extend through the ground floor where a tile under the shaft is not built yet (“Build the lobby on floor 1 first, then extend through it.”), as it already refused one through an unbuilt sky lobby floor. It used to lay plain floor there, where only lobby belongs.
• Placement keeps the metro station’s floor until a station is placed or removed. It used to walk every unit again after each tile a brush, a bridge or an extend laid.
• The conformance lock (expected.json, loader-cases.json, the catalog digests) and the port-edit golden move with these changes. No saved-game, frame or view-layout format change, and the binding’s interface digest is unchanged.

1.21.1 (2026-11-04)

• The tooling-only WASM binding gains startFireAt(id): it starts a chosen flammable room’s fire through the normal outbreak and paid-rescue path, without consuming random draws. It refuses while a fire or emergency choice is active and does not join a pending undo gesture. The TypeScript reference exposes the same test hook so conformance can run a mid-visit fire on both engines.
• No saved-game, frame, view-layout or catalog format changes. The public binding interface digest moves.

1.21.0 (2026-11-04)

• An undo hands back a build’s price only while the build is unused, and that use now lasts. A room the gesture built is in use once it opens (its state leaves construction, which it never goes back to), whatever a move-out or a collection does to it after (“Can’t undo that: the room has opened since. Sell it instead.”).
• A floor or lobby tile, or a shaft, is in use once an hourly pass has run with it standing, since that pass moves tenants in over the floors the tower reaches and shares the crowd out among the shafts: a step records the simulation’s hourly-pass count when its edit began and compares it. Floor a room’s build laid under it counts too, while the room is still being built (“Can’t undo that: its floor has been in use since the clock passed the hour.”, with “Sell it instead.” when nothing stands on the tile).
• A shaft is also in use once anyone rides it, counted by the new Transport::rides: each boarding the dispatch makes, each person in the crowd who gets into a car, and each walker who steps onto stairs or an escalator. The count lives in memory only and is never saved, and every adopted tower forgets the steps, so neither count ever meets a step made on another tower. A step that would take out a used shaft, or take cars or floors back from one, is refused (“Can’t undo that: it has been in use since. Sell it instead.”).
• The advice to sell is left off for a lobby tile and a Classic room that stays for good.
• A gesture that builds a shaft, a car, floors for a shaft or a floor tile, uses it and sells it again keeps that use, so its step is refused (“Can’t undo that: it was in use before it was sold.”), after the builds’ own reasons.
• Doing a sale or a bulldoze again (a redo) does not mind that a room opened or a shaft was ridden, as the sale itself does not, including a redo of a gesture that sold a car and bought floors. It refuses only a room whose tenants, income or state changed since (“Can’t redo that: the room has changed since.”).
• An underground build whose digging searched for treasure is never undone (“Can’t undo that: building it dug for treasure. Sell it instead.”), since the dice and the dug ground are not rewound.
• A step never takes out a floor or lobby tile that a room, a shaft or the story above it still stands on, unless the same step takes those out too, as a sale never does, nor a ground-floor tile that a run of basement tiles hangs from with nothing else to hold it. Nor does it put back a floor or lobby tile above the ground floor over a missing story, or a room on a floor that holds a lobby or on or below the metro station’s row, as a build never could (“Can’t undo that: something in the tower stands in the way.”).
• A refused step that time can make apply stays where it was: not enough money yet, or a room on fire. Any other refusal can never apply, so undo() drops the step and the message adds “Undo again for the edit before it.”, and a redo() refused that way ends the redo trail. Only an edit clears what stands in the way, and undoing that edit puts it back. When a step has reasons of both kinds, the lasting one is reported.
• A unit or shaft an edit touches again after time moved it on inside the same gesture keeps the edit’s own facts from the first look and its live state as it leaves, and a condo that sold meanwhile keeps the price it sold at.
• No saved-game, frame, view layout or catalog change.

1.20.0 (2026-11-04)

• The catalog is now version 6. It gains a rules block with the mode’s rules a frontend shows the player, so a frontend no longer decides them from the mode’s name: variantHouseholds (a sold condo carries its own household of 2 to 5 that prices the sale), previewNamesRefusal (the build preview names the refusal before the click) and scheduleAssist (the elevator schedule’s presets, auto-tune and staffing advice answer). Each is true in Modern and false in Classic, and each is stated from one rule method in engine-rs/src/rules.rs: the condo sale reads GameMode::variant_households, and the schedule preset, auto-tune and schedule facts queries read GameMode::schedule_assist, so the block states the rule those paths apply. (The save loader still keeps a saved household by the save’s mode name; moving it onto variant_households is listed on #1621.) GameMode::preview_names_refusal is a presentation rule the engine only states (it refuses the same builds in both modes). The build gate and the catalog’s available now read one rule too, Facility::available_in, through GameMode::builds_modern_only_kinds. The bridge plan behind the build preview and the auto-bridge keeps one flag per lot tile for the story below, on the stack, in place of a map of lists, so a wide gap no longer costs a scan per tile, and it plans nothing for an empty footprint (which every caller refuses before it plans). The move-in reach memo uses the engine’s fast hasher. Both catalog digests move. No saved-game, frame or view layout change, and no rule, price or simulation result changes.

1.19.0 (2026-11-04)

• New port query and binding method roomTiers() for the Map’s Eval and Pricing views (#343): one record with a roomTier row (id, floor, x, evalTier, rentTier) for every room that carries an evaluation or a rent level, in the view’s room order. The tier codes index two new layout tables, evalTiers (unrated, terrible, good, excellent) and rentTiers (unpriced, noRate, veryLow, low, average, high). A room is rated when the Satisfaction heatmap draws it; its score is Terrible under the keep line a tenant on notice needs (VACATE_RESCIND, 0.4), Good from there up to and including the inspector’s gripe line (GRIPE_WARN, 0.6), and Excellent above it. The Eval tier’s Good line and the inspector’s gripe check now read one predicate (names_gripe); the inspector names a gripe only for the kinds and tenants it inspects. The rent tier is the rung the Classic editor’s picker shows (a price that is not a finite number sits on the Average rung, where the picker places it). For a Modern band price, a price that is not a number reads Average; a price over the neutral price is High, so +infinity reads High (the “rent set too high” gripe’s own test, now one predicate, RentConfig::over_neutral, for the gripe, the over-market check on a tenant’s notice and the tier); a price equal to the neutral price is Average (the batch reprice’s own “on the default” test, now one predicate, is_neutral_price, for both); a price at or under the band’s floor is Very Low; and any other price is Low. One pass over the rooms per call, with nothing written. S8 reads it only on the triggers the Map SPEC lists (while the Map is open on Eval or Pricing: opening it there or picking either tab, a change of game hour, a move of the revision or generation, and every applied rent command or emergency answer), and not more than once a frame. The TypeScript engine does not answer it (the port member is optional). The view layout is now version 12; the save and frame layouts and the catalog are unchanged.

1.18.0 (2026-11-04)

• Two tooling-only binding methods for tests. setWeather(name) sets today’s weather (“clear”, “cloudy” or “rain”), which no save carries; the next day’s roll replaces it, and so does a load, and any other name answers false and changes nothing. clearRetailTallies() clears every unit’s patronage and profit tallies, today and yesterday, the render-only fields no economy path reads. No game command reaches them. No saved-game, frame, view layout or catalog change.

1.17.0 (2026-11-04)

• A tooling-only binding method for tests: setCustomersIn(id, count) sets a unit’s live customer tally, which no save carries, through the setter that logs the unit for the frame, so a test can fill a venue to capacity mid-run. Like a counted arrival, it then mirrors the tally into an attendance venue’s occupants and moves the meal overlay revision. It answers false and changes nothing for an unknown unit or a count that is not a whole number from 0 to 2^53-1. The unit’s kind and its venue cap are not checked, so any unit takes any count in that range. No game command reaches it. No saved-game, frame, view layout or catalog change.

1.16.0 (2026-11-04)

• Two tooling-only binding methods for tests: setClock(minutes) puts the clock at a minute count, forward or back, and runs nothing (the TypeScript sim.clock = new Clock(minutes, calendar); the loop’s pass memos stay, as with advanceClock), and setUnitState(id, state, occupants?) sets a unit’s state by its save name and optionally its occupants, through the setters that log the unit for the frame. Each answers false and changes nothing for input it cannot apply. No game command reaches either. No saved-game, frame, view layout or catalog change.

1.15.0 (2026-11-04)

• The engine keeps the undo and redo steps of the tower it runs, in place of the web host, and a step holds only what its edit changed. New port members and binding methods: undoCapture(label) opens a journal on the tower before an edit gesture’s first change (closing and keeping a gesture already open, if it changed the tower), undoCommit() closes it and keeps the newest undo step only if the gesture changed something (answering whether it did) and ends the redo trail, undoDiscard() closes an open journal and keeps it only if it changed the tower, so no gesture’s edit is left out of the steps, and undoClear() forgets every step. The journal takes the before-image of each unit and shaft an edit touches the first time it touches it, and the cash the edit commands themselves charged and paid back (a build, a shaft, a car, an extension, a sale); it is off the tower while the simulation advances, so time passing is never part of a step, and a payment that is not an edit (a ransom, a rescue, the exterminator, rent, a treasure) is never part of one. A step is as big as its edit, whatever the size of the tower. undo() and redo() close a gesture under way, then apply the newest step and answer [status, generation] as restore does: 1 for a step applied (the generation moves), 0 for a refused step (the step stays available and nothing changes), and 2 when there is no step. A step is refused when the balance cannot pay for it (“Not enough money to undo that.”), when a room it would take out has been used since the step was made: a tenant moved in, it earned, it changed hands, or it burned (“Can’t undo that: the room has been in use since. Sell it instead.”), while such a room is on fire (“Can’t undo that while the room is on fire.”), when it would reprice a condo that has sold since (“Can’t undo that: a sold condo keeps its price.”), and when the tower is not the one the step expects (“Can’t undo that: the tower has changed since.”): a unit or shaft it would take out or restore is gone, or a shaft’s span, cars, stops or schedule moved, or a unit or shaft it would put back is there already, its tiles or column are taken, the floor under it is gone, or putting it back would go past the tower’s cap for its kind (a tower that came in over a cap may be left as far over as the edit found it); a shaft given back its old span needs floor and a free column on every story of it too. Each image in a step says what it expects to find as well as what it does, so an edit made with no gesture open can never make a step move cash for an edit that is not there, or put a room on top of another. A room the gesture itself added is taken out only while its use is the use it came in with, and one the gesture added, that was used and that the gesture took out again, leaves the step refused, so no undo hands back the price of a used room. Applying a step puts back the units and shafts it carries (a removed one returns to its place in the list with its saved record, less the customers and diners who left with it; one edited in place gets back the price, the No Rate flag, the name, the variety, the film policy, or the span, cars, stops and schedule, while the state the simulation moved stays live), adds exactly the reverse of the cash its edit moved, restores the VIP visit day when nothing has moved it since, and ends an elevator’s open extend gesture. The clock, the people, the dice, dug ground and the id counter are not rewound, so no id is handed out twice. undoNotice() is the player’s message (“Undid: Bulldoze”, “Redid: Bulldoze”, “Nothing to undo.”, “Nothing to redo.”), and undoDepths() answers [undo, redo]. Each stack keeps 50 steps. Every adopted tower (loadSave, restore, foundTower, loadVctower, adoptTdt) forgets the steps. No saved-game, frame, view layout or catalog change.

1.13.0 (2026-11-04)

• New port query and binding method floorCongestion(floor): the raw congestion ratio of one floor, the same value hotspot takes its peak from. A floor with no reading (empty, stranded, off the tower) and a floor that is not a whole number answer 0. It walks the rooms once per call, so it is a read for tests and tools; the frame keeps using congestion and hotspot, which are kept per step. The TypeScript engine answers it through Simulation.congestionAt. No saved-game, frame, view layout or catalog change.

1.12.0 (2026-11-04)

• Two card verdicts now come from the engine. The shaftCard record gains a nearCapacity slot (1 when the shaft’s average car load is above 85%, else 0; a shaft with no reading is 0), placed right after utilization, so the slots after it move up by one. A new read-only recyclingDemandMet() on the port and the binding answers whether the working recycling centers can process the whole population. The host used to compare the load with 0.85 and the population with the capacity itself. The transport detail the stats and inspector read also carries nearCapacity. The view layout is now version 11; the save and frame layouts and the catalog are unchanged.

1.11.1 (2026-11-04)

• The .TDT export writes a hotel room that has been rented and now sits clean and empty with the vacant-and-clean stay state (24, 0x18), the byte the original game’s own saves hold for such a room. It used to write a bare 1, which has no stay state, so the original read the room as a sleeping guest and rewrote it as 0x10 when it saved (found by the infested-room round trip on the PC, #1629). Importing either byte gives the same empty room that has been rented, so a round trip through our own importer is unchanged. Seven export digests in the conformance lock move. No saved-game, frame, view layout or catalog change.

1.11.0 (2026-11-03)

• The view’s frame header (VIEW_LAYOUT_VERSION 10) gains seven slots after transports: day, dayOfWeek, isWeekend (0 or 1), quarter and year, all counted from 0 on the tower’s calendar, then weekDays and weekendDays, the calendar’s week and weekend lengths in days. A host shows dates from them and no longer does the date arithmetic itself. The header is 39 slots wide (it was 32), so every record after it moves; read the offsets from viewLayout(). No saved-game, catalog or rule change.

1.10.1 (2026-11-03)

• The .TDT export writes an infested hotel room with the dirty flag (32) and counts it as a dirty room in the people and finance blocks, as a dirty room is. It used to write no flag, so the room re-imported as a clean vacant room. What flag 64 means in the original game is still unchecked (#1629), so it is not written. No saved-game, frame, view layout or catalog change.

1.10.0 (2026-11-03)

• scheduleFacts gains homeFloors: the draft’s homes as the shaft would hold them, one per car, each on the nearest served floor (ties to the lower one), with a car the draft lists no home for at the base lobby. It is empty on a refusal. The host no longer snaps homes to served stops or works out the base lobby itself. The advice answer is unchanged. The staging counts (upTowerCars, lobbyCars) now follow the snapped homes, so a draft with a home on a skipped floor counts that car where the shaft would hold it. The query also borrows the day’s measured ring instead of copying it (autoTuneProposal still copies it, since it returns the curve). No saved-game, frame, view layout or catalog change.

1.9.0 (2026-11-03)

• Two new read-only queries on the port and the binding for the elevator Schedule dialog. scheduleFacts(id, draft, weekendView) (native Simulation::schedule_facts) answers a keyed object: a status (available, not-an-elevator, missing-shaft or invalid-draft), the recommended preset (feeder for an express, rush for a local, null where the mode offers no assisted presets), the advice comparison (ready, insufficient-data or unavailable-in-mode, with the over and short hours: an hour is over when its authored cars reach the measured want plus two, short when they fall two under it and the hour does not already run the whole fleet) and the Simulate staging summary (whether the busiest hour is measured, the busiest hour or the assumed 17:00 down-rush, the cars on shift then, how many of them are homed above the base lobby, and the base and top lobby floors). schedulePreset(id, name) (native Simulation::schedule_preset) answers the rush, balanced, feeder or stage-up-tower preset’s weekday and weekend rows and home floors, or a refusal (unavailable-in-mode, not-an-elevator, missing-shaft or unknown-preset). Classic keeps stage-up-tower (homes only) and the staging summary and gets no advice, recommendation or other preset. Both queries take the working draft in scheduleShaft’s slots (empty for none), write nothing, and carry no wording. The engine now owns the preset rows, the preset staging, the advice margins and the staging counts; the rules are the ones the dialog always used. A shaft that holds no cars (a loaded save can) now answers a no-cars status from autoTuneProposal (it answered unavailable-in-mode in 1.8.0), schedulePreset and the advice of scheduleFacts; a refused scheduleFacts answer carries the advice status refused, and recommended is only ever rush, balanced or feeder. No saved-game, frame, view layout or catalog change.

1.8.0 (2026-11-03)

• New read-only query autoTuneProposal(id, draft, weekendView) on the port and the binding (EnginePortQueries, Engine::autoTuneProposal, native Simulation::auto_tune_proposal). It answers a keyed object: a status (available, insufficient-data, unavailable-in-mode, not-an-elevator, missing-shaft or invalid-draft), each day type’s readiness (warm once six hours of its curve are sampled, sampledHours, and the warm day’s measured 24-hour curve) and, when available, the proposed weekday and weekend rows and home floors. The engine now owns the warm-up gate, the per-hour tuning (load fraction times installed cars, at least one car, at most the cars installed), the staging seed aimed at the busiest served boarding floor and the snap of homes to served stops. draft is the working schedule in scheduleShaft’s slots (empty for none; a home count of 0 marks staging as untouched, which the engine seeds, while hand-set homes are kept). A day that is not warm keeps the draft’s own row. Classic answers unavailable-in-mode with readiness filled in. The query writes nothing: no tower, telemetry, rng, cash, event or save byte changes. The tuning rule itself is unchanged from the dialog’s. No saved-game, frame, view layout or catalog change.

1.7.0 (2026-11-03)

• The tdtExport record gains retailRowsDropped after outOfRange: the shops, restaurants and fast food places past the 512 style rows a 1994 file holds, which the export used to drop without a count. The view layout is now version 9; the save and frame layouts and the catalog are unchanged.
• The .TDT importer’s rebuilt elevator layout (used when a save’s elevator table cannot be read) places each shaft on the nearest columns free of rooms and of earlier shafts over every floor it serves, reads the rooms from the final tower (after parking stalls slide onto their ramps), and leaves a shaft out with a warning when no column is free. The “ends right after its elevators” warning no longer says the stairways could not be read, since the importer still looks for them.

1.6.0 (2026-11-03)

• serviceDiagnostics(id) gains a keyed commercial section: lobbyFar is true when a foot-traffic venue sits more than two floors from the nearest (sky) lobby, which halves its trade, and null for a unit the penalty never applies to (a sky bar is exempt and a venue that earns nothing in the current mode has no trade to halve, as in the income rule). The retail patronage block is now limited to the venues the catalog prices per customer (shop, fast food and restaurant, plus food hall, amusements and boutique bay in Modern), the set the TypeScript reference showed it for. Sky Bar, Nightclub, Spa and Daycare no longer answer retail.active. No saved-game, frame, view layout or catalog change.

1.5.2 (2026-11-02)

• Added maxHousehold to catalog facility entries and economy.garbageCollectHour to the catalog economy. The catalog shape is now version 5, with matching TypeScript/Rust catalog locks and compatibility record; save, frame and view layout versions are unchanged.

1.5.0 (2026-11-01)

• Classic PC .TDT imports now record an explicit per-express-shaft preserveBasementStops provenance flag in saved transport data. Its underground stop choices are retained across ordinary .vctower serialization and reload, including empty and mixed skip lists. Older unmarked towers and Modern shafts retain their existing normalization; the save version and binding layout are unchanged.

1.4.0 (2026-11-01)

• serviceDiagnostics(id) now includes keyed, engine-authored retail facts for commercial venues: patronage, business tier, demand percentage, Modern-mode under/oversupply advice, yesterday’s profit and rain. The inspector’s demand map is memoized; no saved-game, frame or view layout change.
• Editing an older shaft’s hourly duty counts keeps existing legacy home floors unchanged. Explicitly reauthored homes still snap to the shaft’s stops.

1.3.0 (2026-11-01)

• The inspector can read typed, engine-authored service diagnostics through serviceDiagnostics(id), returned to JavaScript as a keyed object. Parking, hotel and housekeeping verdicts and supporting facts are Rust-owned. Numeric frame and tenant records, the view layout, save format and simulation rules remain unchanged.

1.2.0 (2026-10-30)

• The catalog carries four kind facts on every facility entry: commercial, hotel, leaseAmenity and unmetDemand, the engine’s own is_commercial, is_hotel, is_lease_amenity and is_unmet_demand_kind. A frontend reads them instead of keeping its own kind lists. CATALOG_VERSION is 3, so a frontend built for version 2 refuses this catalog, and the catalog digests are regenerated.

1.1.1 (2026-10-30)

• An elevator car the schedule has stood down takes no new riders: a person waiting at a floor does not board a parked car, which never left its home floor. A stood-down car that still has riders aboard keeps running to their floors, answers no hall calls and takes nobody new, then parks when the cab is empty. This moves expected.json for amenities-modern, fixture-split-tower-4 and offshift-schedule-modern. The TypeScript reference engine carries the same rule so the shared lock holds for both.
• A bought elevator car joins the shaft’s duty schedule (Tower::set_cars): in each day type, every hour that ran the whole fleet now runs the new fleet, and every other hour keeps its count. Home floors, stops and unscheduled shafts are unchanged, and a shrink still clamps. No conformance scenario buys a car into a schedule, so the lock does not move; the TypeScript reference mirrors the rule.

1.1.0 (2026-10-30)

• The wedding hall is 28 wide and 5 floors tall in both modes, anchored on floor 100 and rising through floor 104 (WEDDING_HALL_TOP_FLOOR, Kind::highest_story). Nothing is built above floor 100 but the hall. Saves that hold the old 16 wide hall widen it on load, with no save version change.
• Classic: the wedding hall cannot be sold or bulldozed (GameMode::room_is_permanent now lists it, with CLASSIC_WEDDING_HALL_KEPT as its refusal), and floor 100 takes only the hall. The reservation is checked after the shared refusals, so the TypeScript reasons still win where both engines refuse.
• The catalog lock hashes a view of the catalog with the hall’s width and floors left out, on both sides, so the TypeScript table keeps its 16 by 1 hall. catalog_json still reports the real footprint. The digest is regenerated.
• .TDT: the cathedral’s five parts (types 36 to 40) now read and write upward from floor 100 (rows 109 to 113), bottom part first; the importer keys a hall off its lowest part floor and the exporter allows the hall up to row 113.

1.0.4 (2026-10-30)

• Security, medical, housekeeping and recycling build at SimTower’s widths (16, 26, 15 and 25 tiles), and the metro station is 30 tiles wide with a full-width tunnel row. This moves the catalog digest and the conformance checkpoints.
• Nothing can be built below a metro station, its bottom row holds only the station and its tunnel, and the bottom basement row (B10) takes only the metro. A station needs a clear bottom row and nothing under it.
• The v1 to v2 save migration keeps the old widths of those kinds, so old saves re-lay exactly as before.
• The .TDT importer slides parking stalls that the file leaves less than one stall’s width from their neighbor toward the ramp, closing the gap, so a row such as TOWER7’s B5 (a 3-tile and a 1-tile paving piece between stalls) chains to its ramp. A row split by a wider gap stays split.

1.0.3 (2026-10-30)

• The service elevator car holds 17 (Kind::car_capacity), the figure in the Windows Help file, up from 10. The catalog’s carCapacity, the per-car load clamp, and the congestion read follow. The .TDT exporter keeps its old service capacity byte (Kind::tdt_header_capacity), because the byte is unreliable and the referee pins it. The catalog digests and the conformance lock move.

1.0.2 (2026-10-30)

• Classic: GameMode::room_is_permanent replaces housekeeping_is_permanent and also keeps placed security offices, recycling centers and movie theaters (remove_facility refuses with a per-kind message; a gutted shell still clears). Modern sells them. The star-climb-classic conformance scenario no longer sells its security office (it starts one office short of the 3-star gate), so the lock moves.

1.0.1 (2026-10-30)

• The 3-star gate (both modes) needs SECURITY_OFFICES_FOR_THREE_STARS (two) operational security offices instead of one, in the rating evaluation and in the star-gate panel getter. Stars still never downgrade. The star-climb-classic conformance scenario builds a second office and the lock moves with it.

1.0.0 (2026-10-30)

• The Rust engine is the only engine the shipped game runs: every deploy builds with VC_ENGINE=wasm, so there is no TypeScript engine to fall back to and no cohort draw. The TypeScript engine stays in the repository as the reference the conformance lock and tests compare against until it is deleted.
• No change to saves, the frame and view layouts, the catalog or the binding’s declaration. The version marks that the game depends on this engine alone.

0.24.4 (2026-10-30)

• Classic: the metro station’s help to commercial demand and its rain relief now need the station’s platform floor to be served by transport. Modern keeps the any-operational-station rule.
• Housekeeping joins the kinds that cannot be placed underground (no_basement in the catalog), in both modes. Saves that already hold basement housekeeping still load.
• Classic: a placed housekeeping room cannot be sold or bulldozed (GameMode::housekeeping_is_permanent), except a gutted shell. Modern still sells it. Lobby tiles were already refused in both modes.

0.24.3 (2026-10-30)

• A metro station’s unit card reads its elevator access at the platform floor, the floor above the row the station is saved on, the same floor the engine’s own metro rule uses.

0.24.2 (2026-10-30)

• The .TDT importer reads a hotel room’s stay state (checked in, asleep, vacant) from its status byte. Checked-in and asleep rooms arrive with their guests at any hour, and clean vacant rooms arrive empty, so a tower’s guest count matches the file’s hotel lines.
• A hotel suite holds 2 guests, as the finance block of every real save counts it. This moves the catalog digest, the conformance checkpoints and the .TDT export hashes.

0.24.1 (2026-10-30)

• The .TDT exporter writes the stairs table where SimTower keeps it, with the parking and clinic lists, and the importer finds it there (#1501).

0.24.0 (2026-10-29)

• The .TDT export keeps the game clock to the minute, so an exported tower imports with the same time.
• Shops, restaurants and fast food places imported from a save get a style.
• The stairs table is read once per window.

0.23.0 (2026-10-29)

• Real 1997 saves whose express shafts broke the elevator table walk now import.

0.22.0 (2026-10-29)

• Opening hours and households live in the engine catalog (#921, part 2b).

0.21.0 (2026-10-28)

• The port exposes the recycling card’s fill and capacity lines (#1420).

0.20.0 (2026-10-28)

• The port can bulldoze a floor tile, quote a batch price, read a schedule and read the founder mark.

0.19.0 (2026-10-28)

• The frame loop reads the star rating, the emergency and the win from the port.

0.18.0 (2026-10-28)

• The port carries the renderer’s reads.

0.16.0 (2026-10-28)

• The port advances time with one call per frame (slice 7, PR 5a).
• Frame layout version 5, with the binding and contract rows recorded (PR 1d).

0.15.1 (2026-10-28)

• Saves load the same in both engines for a random state of 0 and for hand-edited fields.

0.15.0 (2026-10-28)

• The panel queries are available on the engine (slice 7, PR 1c).

0.14.0 (2026-10-28)

• The port covers the lifecycle, events, log and text getters (slice 7, PR 1b).

0.13.0 (2026-10-28)

• The port covers the player commands and the HUD queries (slice 7, PR 1a).

0.12.0 (2026-10-27)

• Every player command goes through the port. The unit removal scan and the brush move into the engines (#1209).

0.11.0 (2026-10-27)

• The engine reports diagnostics facts for the tenant family (#1215).

0.10.0 (2026-10-27)

• The engine exposes the renderer-facing view (#1213).

0.9.0 (2026-10-27)

• The binding offers an hourly save delta (#1045).

0.8.1 (2026-10-27)

• The TypeScript .TDT exporter refuses or writes forged saves the way the Rust exporter does.

0.8.0 (2026-10-27)

• The panel getters are bound for the facade (#1214).

0.7.0 (2026-10-22)

• Merge leftovers are resolved and star-start semantics are intact.

0.6.0 (2026-10-21)

• The engine view is bound.

0.5.0 (2026-10-21)

• The Rust step driver lands, and the consumer drives time through it.

0.4.0 (2026-10-20)

• The binding answers the command gaps the facade listed (#868, slice 6d).

0.3.0 (2026-10-20)

• The crate is raised to 0.3.0 and its compatibility record is recorded again.

0.2.0 (2026-10-20)

• engineIdentity() and the crate version rule arrive (#963, slice 1).

0.1.0 (2026-10-08)

• First engine: the referee, new game, tower and build paths.