- New functions:
  - New P2P 1v1 race mode: race with a friend without having to set a server using a peer-to-peer connection;
  - Experimental support for servers with client-specified cars and for changing car skins live (some features wouldn’t work for now, update for CM is coming soon).

- Major fixes:
  - Linear color space: speculars fixed;
  - Some track physics objects missing on any collisions fixed;
  - The crash caused by missing cache subfolder “meshes_metadata” is fixed;
  - IMGUI: fallback fonts fixed, rare characters should work in titles and such;
  - Shadows computing now takes base surface normal into account as well, fixing an issue with the main building on Spa;
  - A few issues causing GPU to crash (related to navigators, particles, filters, car swap and more) have been fixed;
  - Some of NaN rendering glitches with refracting headlights fixed;
  - Fixed some crashes with cars with encrypted colliders;
  - Visual tyre wetness and AI alterations getting stuck on rain deactivation fixed;
  - Surfaces FX audio fixed.

- Physics:
  - “Extra contact points” experiment is back and enabled by default, no longer moves contact point laterally so it won’t affect FFB;
  - New physics experiment optimizing colliders for track physics objects;
  - New physics experiment tweaking track physics objects without explicit configuration (CoG fix, a bit of damping, a bit of friction);
  - New physics experiment equalizing pits check thresholds across Assetto Corsa (available online as `[PHYSICS_EXPERIMENTS] EQUALIZE_PITS_CHECK=1`);
  - New options in general disabling lap invalidation by AI or Physics API;
  - Automatic Sine→Perlin upgrade (affecting invalid surfaces only) now upgrades to Simplex instead;
  - Procedural surface noise better handles multiple tyre rays;
  - A few other improvements for surfaces with procedural noise (better car placement, better ground plane computation);
  - Cars occasionally exploding on certain surfaces fixed.

- AI:
  - Steering is smoother (physically) at speeds below 7 km/h;
  - Trajectories fixed (“cautious steering” tweak was messing things up);
  - AI debug app now shows actual AI inputs instead of smoothed ones;
  - If the “Tweak autopilot switching” option is disabled, AI inputs smoothing, as well as some other tweaks, will work properly anyway;
  - “RACK_TRAVEL_LUT” stops working with autopilot as well (previously, it would stop for AIs to keep them safer, but not for the autopilot making testing more difficult).

- Extended track physics:
  - New `COG_OFFSET=AUTO` for track object physics parameters applying CoG fix;
  - `COLLIDER_DEBUG` from custom track object collider parameters removed, replaced with a checkbox in CSP Debug app;
  - New `_EXT_PERLIN_NOISE=SIMPLEX` for track surfaces to use Simplex noise (basically Perlin but a bit better).

- Audio:
  - New audio tweak: using traction control intensity for its audio volume (enabled by default);
  - Collision audio for hits no longer cuts off, instead, new events are created live;
  - CSP no longer plays hit audio for overwhelmingly scraping collisions, or scrape audio for hitting collisions;
  - CSP ambience audio is no longer affected by doppler shift at all;
  - Mumble voice chat: audio volume fading when talking or listening is disabled.

- New main menu:
  - Better setup titles (let me know if I missed any abbreviations);
  - If any setup tab title has a lower-case letter, CSP won’t adjust case;
  - Leaderboard uses custom driver icons, if set;
  - Look and behavior of disabled setup items improved;
  - Scrolling of setup tabs has been fixed;
  - `EXT_VISIBLE_WITH` works from the start, not waiting for something to change;
  - Hidden tabs are fixed, no longer can be selected;
  - Tab reset works for more types of tabs;
  - Hold Shift and click on car preview in the main menu to change color in a single-player session.

- Other UI changes:
  - Position of warning icons (the ones in the top left corner) and race flags fixed;
  - Options to disable warning icons and hide racing flags, by default icons hide with Ctrl+H;
  - “Center UI” option got an extra variant centering apps bar (and tasks switcher) as well;
  - New pause menu: buttons don’t get clipped with photo mode anymore, buttons shift down if the menu has been moved to the bottom half of the screen;
  - Recently added assists editor is optional, with a setting to turn it off;
  - Starting lights shift upwards when the main menu is opened.

- Default Weather FX style: 
  - Brightness adjusted;
  - White reference point accounts for post-processing exposure, ensuring the same brightness in different conditions (LCS only);
  - Fog is a bit less bluish;
  - Glare in the virtual mirror is reduced.

- Particles:
  - Piece and spark particles: collisions with track improved, sparks use local heightmap, issue with sparks-car collisions misbehaving fixed;
  - Fireworks use additive blending;
  - Smoke behavior adjusted, positional variance no longer applies to most smoke types;
  - Velocity of flame particles in track configs with flame intensity above 1 fixed;
  - Particle sizes adjusted: pieces have a small chance of being large, flames are larger if fast.

- Grass FX:
  - Localized randomization no longer jumps with origin shift;
  - Shading improved;
  - Grass disappearing for a frame with origin shift in OpenVR mode fixed.

- CSP Debug app:
  - A checkbox showing outlines for track physics objects fixed;
  - Dragging improved: forces are critically dampened to prevent oscillations, multiple cars can be dragged at once, track physics objects can be dragged as well;
  - Click-to-teleport is merged with dragging, allows to orient car;
  - Dragging tool allows to push or pull the car as well.

- Hotlap with multiple ghosts:
  - Laps done with AI (with AI lap invalidation disabled using the new option) are marked;
  - Copying of the best record to the place where AC would originally store a ghost is fixed, now includes layout ID.

- Miscellaneous:
  - VR tweaks: options “Custom VR HUD” and “Skip post-processing” are enabled by default (it just looks so much better this way, and it’s compatible with LCS too);
  - AC no longer raises an error with empty “aero.ini”;
  - Other fatal AC errors are shown properly;
  - Blown tyres of remote cars affect wheels positioning with custom motion enabled;
  - Remote cars: angle of front wheels got a tiny bit of smoothing, fix for steering wheel angles range improved;
  - CSP shows a warning if a Lua script takes more than a second to do something;
  - If country name is missing, tooltip for its flag in chat will be hidden;
  - Nice Screenshots: accumulate HDR summation is marked as not compatible with scriptable filters, will be paused when filters are active;
  - Snow/ice definitions for “ek_akina_snow”;
  - Timezone for “rt_lime_rock_park” fixed, added heading angle;
  - AC timing with fewer than four cores, or with multithreading disabled, improved;
  - Vintage scriptable filter: small update reducing dithering;
  - “Show important steering wheels” tweak improved;
  - Old tweak getting dynamic object balloons to move with wind has been fixed and improved;
  - Slightly improved taskbar closing behavior;
  - “Disable Steam interface” option renamed and reset, in case somebody enabled it by mistake (now, CSP won’t offer to activate it anymore);
  - Neck FX temporarily pauses photo app FOV slider when changing FOV, for both to work better together and fix some issues with other components;
  - Hotkey to toggle virtual mirror can be changed (CM update allowing to bind F… keys is coming soon);
  - Active Steam overlay stops mouse hovering effects of IMGUI;
  - With CSP flames enabled, original flames no longer waste time looking for textures;
  - Rendering debug: new option forcing informative crashes on D3D11 errors;
  - Crash reports are detailed by default, compact ones are pretty useless.

- Other fixes:
  - Issue with wheels increasing in size online without custom motion in long races fixed (I would highly recommend to enable custom motion though);
  - Analog odometers no longer break some textures with HDR enabled;
  - Car LODs acting strange with 20+ cars in a frame are fixed;
  - Decoding of animated GIFs fixed;
  - Misaligned colliders of some track physics objects on Barcelona fixed;
  - Walking Out: pause is working correctly when walking around;
  - Synchronization of dynamic objects across clients online fixed;
  - Borderless AC window saves its size and position properly;
  - A couple of core fixes to prevent memory corruption happening in some rare cases;
  - A few crucial fixes for memory profiler;
  - Headless mode disables all the input (keyboard, gamepad and wheel), few other fixes;
  - Fallback LOD no longer takes a frame to appear if other LODs are available;
  - Flashing for jumped cars, or from `ac.highlightCar()`, fixed, shouldn’t affect grass anymore;
  - Resetting extrapolation of remote cars on teleports slightly improved.

# Configs

- Car & track configs:
  - New `[TYRES_FX] RADIUS_OFFSET` parameter allowing to alter visual radius of tyres;
  - Glass materials: new `NormalMapUVMult` parameter;
  - Brake Disc FX: compute of default value for `CERAMIC` adjusted to make them less frequent;
  - A few improvements for live car config reloads;
  - `BLIND_SPOT` car input and `ac.getCarBlindSpot()` fixed, now returns distances to the cars in front (as Z) and behind (as W) as well;
  - `[DATA] DI_…_…` modifiers for digital instruments can use “BASE” instead of an index to affect all of them;
  - `[DATA] DI_…_ALPHA` affects first version of text nodes as well;
  - Track conditions tool shows input values as well;
  - New `[BASIC] SEASONS_DEACTIVATION_AWARE=0` to fix tracks that don’t expect `YEAR_PROGRESS` to be -1 when season changes are disabled, on by default for all but “dousojin_touge” and “dousojin_touge_1990”;
  - Box guessing for track object colliders (trying to replace a mesh with a box with custom track physics) improved.

- Extended configs for online servers:
  - Use `[CUSTOM_PHYSICS] EXTRAPOLATE_STATE=1, 1, RAW` to try a new approach to avoid shaking;
  - Use `[CUSTOM_PHYSICS] SMOOTHING_FACTOR=100` to make movement of remote cars more snappy and less smoothed (lower value for smoother movement, default value is 250);
  - Add `[EXTRA_DATA] VR=1` to sync the state of drivers using VR (requires AssettoServer);
  - Use `[EXTRA_RULES] ALLOW_PITS_JUMP=1` to allow jumping in pits by holding Ctrl and clicking on car preview;
  - Set `[PHYSICS_EXPERIMENTS] EQUALIZE_PITS_CHECK=1` to equalize thresholds of AC checking if car is in pits or not (experimental);
  - Jump limit slightly improved, more sensitive to jumps side-to-side, default time reduced from 5 to 2 seconds, flashing is only present if the car intersects another car, cars no longer flash if collisions are disabled via Physics API.

# Scripting

- Common API:
  - New properties for `ac.StateSim`: `.isTrackOpen`, `.isTimeOffsetIgnored`, `.timePostOffset`, `.timePhotoModeOffset`, `.isAltOnlineRace`;
  - New `ac.checksumCRC32()`;
  - New `string.urlDecode()`, `string.urlParse()` and `string.xor()`;
  - New `mat4x4:getEuler()` returning Euler vectors from a matrix as a counterpart to `mat4x4.euler()` creating a matrix from Euler vectors;
  - `ac.INIConfig.parse()`: use `@car:N` as include folder for “read()” expressions to work as well;
  - New `ac.getAssists()`;
  - New `ac.onCarSwap()`;
  - Function `ac.areShapesColliding()` fixed: debug outlines for cylinders and capsules are aligned correctly, car colliders account for graphics offset, new `physics.Collider.Track()` allowing to check for collisions with the track;
  - New `ac.getCollidingShapesContacts()` returning actual contact points;
  - New argument for `coroutine.create()` for flags: raise errors, start coroutine immediately;
  - New `insideCar:yes`, `actsAsLED:yes` and `actsAsAnalogInstrument:yes` queries Scene API;
  - Functions raycasting physics geometry got an argument for taking procedural noise into account;
  - New `coroutine.sleep()`;
  - Coroutines support improved (please report any malfunctioning functions).

- Shared libraries:
  - New `shared/promise` with a custom fast JS-like Promises implementation;
  - New `shared/utils/ntp` library for querying precise time using NTP protocol (can help with syncing for alternative online modes);
  - New `shared/utils/luasteam` for full access to Steam API available to all scripts with I/O access (forked version of `luasteam` with a few more functions and a bunch of small fixes);
  - New `shared/utils/parcel` for exchanging small bits of data;
  - New `surfaces.raycastDetailed()` in `shared/sim/surfaces`;
  - `shared/utils/signing`: new `signing.check()`, new `{CSPVersion}`, `{CSPVersionCode}` and `{UniqueMachineKeyBase64Trimmed}` for signing format string, queries to quickly and easily verify integrity of cars and tracks, as well as AC’s “surfaces.ini”, `verify` function can handle absolute paths, other fixes;
  - `shared/sim/fireworks` library is more responsive.

- Render API:
  - New `main.smoke` render event for `render.on()`;
  - `render.circle()` and others: argument for white reference point brightness correction.
  
- I/O API:
  - New `io.compress()` and field `compress` for `io.extractFromZipAsync()` for applying NTFS compression, `remote_assets` files are compressed by default;
  - `io.` functions accessing file times (such as `io.lastAccessTime()`) can be used to change file times as well now.

- UI API:
  - Horizontal thin scrollbars (new argument for the function, or, you can use `bit.bor(ui.WindowFlags.HorizontalScrollbar, ui.WindowFlags.ThinScrollbar)` for a window with horizontal scrollbar);
  - `ui.progressBar()`: pass `math.nan` for `progress` for indeterminate progress bar;
  - `:linkToSimulationSpeed()` of GIF players fixed;
  - Using `ui.unloadImage()` now lets CSP unload “dynamic::hud::redirected::N” buffers if unused.

- Gameplay API (available to apps, online scripts and more):
  - New `ac.resetDynamicTrackObjects()` in Gameplay API allowing to reset dynamic track objects;
  - New `:redirectLayer2()` returning duplicate flag as well, `:redirectLayer()` is deprecated;
  - `ui.registerOnlineExtra()`: argument to set a tooltip message.

- Game API (available to apps and New Mode scripts only):
  - New `ac.setTrackCoordinatesDeg2()` (`ac.setTrackCoordinatesDeg()` is mixing up X and Y of coordinates);
  - New `ac.debugTrackColliders()`.

- Lua apps:
  - New `ac.sendKeyboardButtonEvent()`;
  - `ac.getSetupSpinners()`: new `visible` field;
  - New `ac.getSetupTabs()`.

- New Modes:
  - New experimental `ac.overrideSession()`;
  - New `[TWEAKS] ALT_ONLINE_CARS=<number>` adding extra “remote” cars that can be driven by the script, with a new `shared/sim/altonline` library to control them, as well as other values allowing to create proper custom online modes and more, see “p2p-1v1” for an example;
  - New `[TWEAKS] DYNAMIC_TRACK_OBJECTS_SEED` overriding random seed used for arranging track objects;
  - Add `[TWEAKS] VERIFY_STEAM_API=1` for CSP to check if Steam is actually available at the launch;
  - Manifests of New Mode scripts can use INIpp features, allowing to do things like activating tweaks based on “race.ini” or “settings.ini”;
  - Scripts can access `ac.startBackgroundWorker()`.

- Physics API:
  - New `physics.setPenalties()`, `physics.setWrongWayPenalty()` and corresponding state fields in `ac.getSim()` (also, `.allowedTyresOut` updates live properly);
  - New `physics.setAssists()` and `ac.onAssistsChanged()`, `physics.setAssists()` can also be used to block out assists editing;
  - `physics.RigidBody()`: alignment of debug outlines for cylinders and capsules is fixed as well;
  - `physics.overrideRacingFlag()` works better if called every frame;
  - New `physics.getTrackObjectStatus()`, `physics.getTrackObjectPointVelocity()` and `physics.addTrackObjectForce()` for physics workers;
  - Enabling AI for cars online fixed;
  - Logic for laps invalidation caused by usage of these functions slightly improved, invalidating less often, no longer invalidating when applying to AIs in offline races.

- Car physics scripts:
  - New `ac.addCosmicForce()` and `ac.addCosmicTorque()` for adding forces to cosmic suspension;
  - Physics debug lines: brightness fixed, `.mult` of `rgbm` is taken into account, option to draw a dashed line.

- Other script-related changes:
  - Lua profiler updated, cleaner and more informative, no longer freezes AC;
  - Lua Debug app: texture viewer no longer conflicts with Objects Inspector, graphs for `ac.debug()` with number adjusted;
  - Calling `script.asyncUpdate()` is temporarily disabled until I figure out why it explodes at the start once in a dozen of runs;
  - Docs for states fixed, 0-based arrays use custom tables instead of array syntax to improve compatibility with Lua Language Server plugin;
  - Some of LuaJIT functions, especially the ones returning complex entities like INI files, should be faster;
  - New Python function `ac.ext_isLapInvalidated()`.