MafiaCoop 0.17.1 (pre-release, checked on one PC, not yet tested on two PCs)

Pre-release. Checked on one PC with two copies of the game, not yet tested on two PCs. 0.17.1 fixes the bugs found in 0.17.0, most importantly one that could overwrite the host's story save. Anyone on 0.17.0 should update.

Download MafiaCoop-0.17.1.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.17.1-symbols.zip holds the PDBs and is only needed to read crash dumps. Both players need 0.17.1: it can't play with 0.17.0. A player on another version is turned away with a "version mismatch ... Both players need the same MafiaCoop version" message.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one), with Steam running
• Everyone in a session on 0.17.1. Joining by IP needs UDP port 27960 open on the host.

Fixed in 0.17.1

• Your story save is safe again. In 0.17.0, when the host of a co-op Free Ride died, the game wrote over his real story save. 0.17.1 fixes this. If you hosted Free Ride in 0.17.0 and died, check your story progress. Backing up Documents\My Games\Mafia Definitive Edition before playing a pre-release is still a good idea.
• Motorbikes: the other player's character no longer keeps falling off and getting back on the bike, over and over, for the whole ride. After getting off, his character no longer stands on top of the parked bike.
• Traffic: the copies of the host's moving cars now stay in their lane instead of drifting up to 2 m to the side.
• The CO-OP entry in the main menu was missing in about one start in three. Now it is there every time.
• Getting in and out of cars:
  • The other player's character no longer stays stuck in a car after he has got out.
  • Getting into a back seat no longer throws the character straight back out.
  • Riding along in someone else's car now shows you in that car.
  • Getting into a new car right after leaving your old one no longer mixes the two cars up.
• Car damage: a crashed car no longer flips between repaired and damaged on the other player's screen.
• The leash: a friend pulled back to the host in a car no longer falls through the street.
• Police: a friend's game no longer shows a police car of its own that the host doesn't have.
• Rejoining: coming back into a session no longer waits 15 seconds for a car that had already gone.

Checked on one PC (two copies of the game)

• Free Ride together on foot, driving together, riding along in both seats both ways, the motorbike, the leash in a car, a friend downed far away, leaving and rejoining, and a crime near the host. The final build passed every automatic sync check; the longer scenarios passed apart from a few borderline numbers.
• The start of CHAPTER 2: TAXI together (up to the taxi stand).
• No save or profile file changed.

Known issues

• Not tested on two PCs yet: all of 0.17.x. Steam, real internet latency and two different PCs have not been tried with it.
• Please send your logs: after playing, both players send the newest zip from the logs\bundles folder next to MafiaCoop.exe, or the ...-recovered.zip after a crash.
• Motorbike: when the game keeps throwing the rider's character off the bike on the other player's screen, it is put on the saddle and kept there for the rest of the ride.
• A character sitting in a car's front or driver seat is occasionally thrown out of it on the other player's screen.
• Once in testing, the host's world reloaded after he got into a taxi.
• After rejoining, the lobby shows READY instead of JOIN GAME for a few seconds.
• A player sitting in a car can't be shot by the other players, not even through an open window.
• Parked cars, trams and boats are still each game's own.
• Not reached in any test yet: JOIN FRIEND between two PCs, chapters on two PCs, reconnecting over Steam, doors, picking up items, grenades, three or four players.

Full details: CHANGELOG.md. Core: v0.14.1 (changes).

MafiaCoop 0.17.0 (pre-release, checked on one PC, not yet tested on two PCs)

Pre-release. Checked on one PC with two copies of the game, not yet tested on two PCs. In 0.17.0 the host's game runs the whole world: traffic, police, pedestrians and enemies. Your friends see copies of them, and their own games make none. This release also writes much more detailed logs, so after the next test we can find out exactly what went wrong. Please send them after you play (see below).

Download MafiaCoop-0.17.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.17.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Both players need 0.17.0: it can't play with 0.16.0. A player on another version is turned away with a "version mismatch ... Both players need the same MafiaCoop version" message.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one), with Steam running
• Everyone in a session on 0.17.0. Joining by IP needs UDP port 27960 open on the host.

New in 0.17.0

• The host's game owns the world. Traffic, police cars, pedestrians and enemies come only from the host's game, so everyone sees the same cars and people in the same places. A friend's game no longer spawns its own traffic, police or pedestrians.
• The leash. Mafia only brings the streets to life around its own player, so far from the host a friend's streets would be empty:
  • From 300 m away from the host the friend sees a warning.
  • Beyond 400 m, a 10-second countdown starts. Coming back under 380 m stops it.
  • When it runs out, the friend is put back beside the host, in his car if he is driving.
  • Nothing counts during loading screens or cutscenes, or while the host is paused.
  • The host can change the distances in his MafiaCoop.ini: leash_warn_m, leash_max_m and leash_countdown_s. His numbers count for everyone.
• Enemies a friend reaches first stay hidden on his game until the host's game has them, so nobody fights an enemy the host doesn't have.
• Fixes from the one-PC checks:
  • Pedestrian copies keep up with the people they copy.
  • A player whose character the game removed is back in under 2 seconds (it took 5).
  • Traffic far from a friend no longer keeps putting its drivers back.
  • A friend's car copy no longer hangs back after a crash into a wall.
  • A friend pulled back by the leash no longer falls through the street.
• Session logs to send. At the end of every co-op session, and when you close the game, one zip with everything about that session goes into the logs\bundles folder next to MafiaCoop.exe. It is named like MafiaCoop-20261021-201500-host.zip or ...-guest.zip, and your password is not in it. If the game crashed, a ...-recovered.zip is made the next time you start it.

Checked on one PC (two copies of the game)

• Worked:
  • A friend's own traffic and pedestrians switched off.
  • The host's pedestrians, enemies and traffic shown on the friend's game.
  • Players on foot and in cars staying in step.
  • The leash warning, countdown and pull.
  • Joining in under 5 seconds.
  • The new logs and zips.
  • No save files changed.
• Still off:
  • Copies of moving traffic cars were sometimes up to 2 m from the host's cars.
  • After the host got off a motorbike, his character on the friend's screen stood on the parked bike until he moved.
  • One of the friend's own cars stayed visible for 10 seconds before it was hidden.

Known issues

• Not tested on two PCs yet: all of 0.17.0. Steam, real internet latency and two different PCs have not been tried with it.
• Please send your logs: after playing, both players send the newest zip from the logs\bundles folder, or the ...-recovered.zip after a crash.
• A player sitting in a car can't be shot by the other players, not even through an open window.
• After a player gets off a motorbike, its copy may stay on the other screens for up to a second.
• Parked cars, trams and boats are still each game's own.
• Not reached in any test yet: JOIN FRIEND between two PCs, chapters on two PCs, reconnecting over Steam, doors, picking up items, grenades, three or four players.

Full details: CHANGELOG.md. Core: v0.14.0 (changes).

MafiaCoop 0.16.0 (pre-release, not yet tested in game)

Pre-release. Not yet tested in game on two PCs. 0.16.0 fixes the problems found in the 2026-10-18 (one PC) and 2026-10-19 (two PCs) tests and rewrites how the games stay in step: the other players, their cars, enemies, pedestrians, traffic and the time of day. All of it is checked by automated tests only, so expect rough edges and please send the logs after you play.

Download MafiaCoop-0.16.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.16.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Both players need 0.16.0: it can't play with 0.15.0. A player on another version is turned away with a "version mismatch ... Both players need the same MafiaCoop version" message.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on 0.16.0; joining by IP needs UDP port 27960 open on the host

Worked in the 2026-10-19 two-PC test (with 0.15.0)

Steam invites and joining over Steam, the lobby, movement, riding along in a friend's car, the host's traffic on a friend's game, car damage, the host's police chasing a wanted friend, Free Ride death and respawn, punches landing, a real gamepad in the co-op panels and leaving cleanly. 0.16.0 changes several of these, so they need checking again.

New in 0.16.0, not yet tested in game

• Smoother players: the other players walk, run and stop like they really do, closer to where they are, without sliding back.
• Cars: a friend's car drives at its real speed (it ran at about a quarter), drives on its own physics instead of being pinned, and looks like his car (variant, colours, plate). One wheel, one driver. Cars parked before you joined are there.
• Shooting each other works (bullets never hurt a player in the test). Punches lock on to a player in front of you.
• Enemies and police: each enemy is run by one game only, so the host's cops chasing a friend are in the same place on both screens.
• Pedestrians are shared, and a pedestrian you kill dies on every game.
• Traffic is shared wherever players are, also between two friends far from the host, without cars popping.
• Time of day follows the host without jumps.
• Fixes from the tests: punches and throws on the other player's character, the minimap marker, damage after an explosion, seats after a reload, a wanted friend's police level running down, the garage file no longer changed by co-op, motorbikes, swimming, a paused game, traffic losing its drivers, changing character.

Known issues

• Not tested yet: all of 0.16.0. Please zip the whole logs folder on both PCs after playing and send both.
• A player sitting in a car can't be shot by the other players, not even through an open window.
• After a player gets off a motorbike, its copy may stay on the other screens for up to a second.
• Car damage and car colours aren't shared for traffic that a friend's game spawned.
• Not reached in any test yet: JOIN FRIEND between two PCs, chapters on two PCs, reconnecting over Steam, doors, picking up items, grenades, three or four players.

Full details: CHANGELOG.md. Core: v0.12.0 (changes).

MafiaCoop 0.15.0 (pre-release, mostly not yet verified in game)

Pre-release. Most of what is new is not yet verified in game. 0.15.0 had a first test on one PC (two copies of the game, Free Ride, CHAPTER 2: TAXI, the start of CHAPTER 13: SALIERI). Verified there: car signals, failed missions in one load, and the police fix. Everything else below is written but not yet verified in game, and the test found some problems (see Known issues). Read them before you play.

Download MafiaCoop-0.15.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.15.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone needs 0.15.0: the messages and the protocol version changed, so 0.14.0 can't join.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on the same mod version; joining by IP needs UDP port 27960 open on the host

Verified in game

• Car signals: headlights, indicators, horn, siren and police beacon of the car another player drives show on your screen.
• Failed missions take one load: no more short stop in a Free Ride world. When the host fails, everyone goes back to his checkpoint with him. When a friend fails, the host decides whether he rejoins at once or waits. Checked for the host's and the guest's failure in Taxi.
• Police fix: a wanted friend no longer makes the host wanted.

New, not yet verified in game

• Fights and moving around:
  • Punches, counters, takedowns and throws are sent to the other players' characters. The punch itself doesn't show yet (see Known issues).
  • Jumps, vaults, ladders, cover slides, sneaking, the medkit and carrying bodies show on the other players' characters.
  • Enemies only a friend's game spawned now show on the host's game too.
• Cars:
  • The other player's character stays in its seat. Riding along waits until the driver sits at the wheel.
  • A mission car replaced by a copy comes back when the driver parks and gets out.
  • Near the host, a friend sees the host's traffic and police cars.
  • Dents, parts, tyres, fire and explosions show on every game.
• The world:
  • Doors are shared: open, close, kick, unlock and lockpick.
  • Weapons on the ground and pickups are shared, and the host decides who takes them.
  • Explosions show on every game as a harmless picture, and a grenade's flight is drawn on the other screens.
  • Wanted levels are shared, and the host's police chase a wanted friend near the host.
• Map: every other player is on your minimap and map with his name, on foot and in a car.
• Connection:
  • Reconnect: a dropped player's game rejoins by itself for up to a minute and gets his place back.
  • Three or four players.
  • Lower latency (core 0.11.0).
  • JOIN FRIEND lists your Steam friends who play and what they're doing.
• Gamepad: a real controller works in the co-op panels, and the footers show pad buttons or key names, whichever you use. Fixed after the test: closing a panel with a pad button no longer blocks the keyboard on the loading screen.

Known issues (from the test)

• Punches don't show: punches and throws don't show on the other player's character. The real hit still lands.
• Map marker: the other player's marker couldn't be found on the minimap, although the logs say it's there.
• Car look: a player's car shows as another variant and colour of the same model on the other screen.
• Damage after an explosion: after a car blew up, the host's game took the copy's damage report as a repair.
• Seats after a reload: after a friend's game reloads at a new checkpoint in a car, the host may see the friend's character hidden in the car instead of seated.
• Police level: a wanted friend's level runs down on his own game while the host's police chase him.
• Garage: a co-op CHAPTER writes the player's garage (garage.pf in the profile). Your story saves are never loaded or changed.
• Not tested yet:
  • doors, items, enemies only a friend's game spawned, and the mission car coming back after parking
  • three or four players
  • two PCs over Steam
  • a real gamepad
  • JOIN FRIEND with a friend
• After a test, zip the whole logs folder on both PCs and send both.

Full details: CHANGELOG.md. Core: v0.11.0 (changes).

MafiaCoop 0.14.0 (pre-release, fixes untested)

Pre-release. The fixes are not yet tested in game. These are fixes from the first test of 0.13.0 on two PCs. Every session now also writes a detailed sync record, so the next test can be measured. Read the known issues before you play.

Download MafiaCoop-0.14.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.14.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Both players should use 0.14.0. The messages are the same as 0.13.0, so a 0.13.0 player can still connect, but only 0.14.0 has the fixes and writes the records.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on the same mod version; joining by IP needs UDP port 27960 open on the host

Fixed (from the 0.13.0 test)

• Cars didn't roll on the other screen. Every car the other player drove stopped using its own physics within seconds and went back to being moved every frame.
  • The copy's engine is now started and kept running.
  • The copy is given its speed back after every correction.
  • If it still gets stuck, its physics is tried again after 5 to 40 s instead of never.
  • The log checks three times per car whether moving a car stops it.
• Running and sprinting players were up to 3 m ahead of their character. The game's AI sprint is slower than a player's.
  • The character now runs up to 1.8x its normal speed and learns a slow gait faster.
  • When even that isn't enough, the missing speed is made up with small steps, so it keeps up instead of being put back every few seconds.
• The car door animation was cut short after 1 s. A setting was read before it was set; the character now gets the full 4 s.
• Characters thrown out of seats still happens, but every time it does the log now says how.

New: sync records

• Every co-op session writes logs\trace\mafiacoop-<date>-<time>.trace. It records:
  • every position sent and received
  • what the mod decided for every character and car
  • what the game really did, such as the car controls, engine, gear and front wheel angle
  • NPC positions
• That's about 250 MB an hour; only the newest 20 files are kept.
• The last five logs are kept instead of one.
• After a test, zip the whole logs folder on both PCs and send both.

Known issues

• None of these fixes have been tried in game yet.
• Lights, horn, siren and indicators aren't synced.
• Enemies only a friend's game spawned (he got somewhere first) are his alone. The host doesn't see them.
• Mission cars partly done: handing the car back when the host gets out wasn't checked. Ambient traffic, pedestrians and police are each player's own.
• Failed missions still take two loads. A mission timer running out wasn't tested.
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels weren't tried with a physical gamepad.
• No automatic reconnect after a disconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints

Steam invites between two PCs work (checked in the 0.13.0 test).

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.

MafiaCoop 0.13.0 (pre-release, untested)

Pre-release, not yet tested in game. Other players should now look like players: they walk with real animations instead of sliding, car wheels turn with the driver's steering, and name tags show Steam names. This was built from reading the game's code and has not been played yet, so expect rough edges and read the known issues.

Download MafiaCoop-0.13.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.13.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone in a session needs 0.13.0. 0.12.x can't join it because the player messages changed.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on mod version 0.13.0; joining by IP needs UDP port 27960 open on the host

New in 0.13.0

• No more sliding. Other players walk, run and sprint with the game's own animations at their real speed. Their position is only corrected when they are clearly off: gently beyond 0.9 m, and snapped into place when far off or stuck.
• Starting, stopping and turning on the spot follow the player smoothly. Sprints show, and jumps and falls no longer count as stuck.
• Getting into cars: the character walks to the door and gets in with the game's animation when the car is standing still.
• Cars show the driver's controls. The front wheels turn with his steering, and his throttle, brake and handbrake are applied (brake lights, engine). The car moves with its own physics plus a small correction, so its wheels roll. If a car's physics can't keep up on your game, it is moved the old way (logged).
• Steam names on name tags, in the lobby and in the panels, instead of HOST / GUEST. CO-OP SETTINGS > NAME shows your saved name.

Known issues

• None of the new sync has been tried in game yet. Report sliding, odd walking, cars that jitter or wheels that don't turn (logs: %TEMP%\MafiaCoop).
• Lights, horn, siren and indicators aren't synced.
• Enemies only a friend's game spawned (he got somewhere first) are his alone. The host doesn't see them.
• Mission cars partly done: handing the car back when the host gets out wasn't checked. Ambient traffic, pedestrians and police are each player's own.
• Failed missions still take two loads. A mission timer running out wasn't tested.
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels weren't tried with a physical gamepad. Steam invites between two different PCs and accounts aren't fully tested (joining by IP is the tested route).
• No automatic reconnect after a disconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.

MafiaCoop 0.12.0 (pre-release)

Pre-release. Enemies that only the host's game brought into a fight now show on a friend's game, so a friend is no longer shot by enemies he can't see. Read the known issues before you play.

Download MafiaCoop-0.12.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.12.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone in a session needs 0.12.0. 0.11.x can't join it because the NPC messages changed (each NPC's state now carries its character and its shots).

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on mod version 0.12.0; joining by IP needs UDP port 27960 open on the host

New and fixed in 0.12.0

• Enemies only the host's game spawned now appear for friends. Each game brings in a fight's later waves when its own player gets there. Before, an enemy the host's game had brought in (the host went round the back first) shot at a friend without being seen. Now the friend's game spawns a copy of it: the same character as the mission's own, with the host's weapon, moving and firing as the host's enemy does.
  • The friend can shoot and kill the copy, and the host's enemy dies with it. When the host kills it, the copy dies too.
  • The copy doesn't run a fight of its own. The host's enemy already shoots at the friend's character on the host's game, and those hits reach the friend as before. If a copy's own bullet still hits the friend, the damage is given back.
  • If the friend's own game spawns that enemy after all (he walks there himself), his own takes over and the copy goes, so there are no doubles. Copies also go with a reload, during cutscenes, when the enemy gets into a car, beyond 90 m, or 12 s after dying. At most 10 at a time.
• Characters standing at the same spot on both games are only matched when they are of the same kind. Before, the host's kitchen machine gunner could be matched with the friend's kitchen rifleman standing there.
• Checked in Bon Appetit's restaurant fight with two games on one PC, three sessions of 22-24 minutes each:
  • The kitchen, yard, balcony and alley gunners that only the host's game had brought in appeared on the friend's game (15 copies, two of them forced in a test). Standing still they stayed within 0.0-0.3 m of the host's enemy; running, they were about a second behind. They fired when the host's enemy fired.
  • The friend killed five of them, and the host's enemy died each time. The host's kills removed them.
  • The whole fight was cleared to its last enemy: the host circled round behind the four attackers in front of the restaurant, which could then be killed. One of them was killed by the friend.
  • No crash, including three failed-mission reloads.

Tested, not finished

• Right after the cleared fight, the chapter failed each time on the way to Salieri. The automated tests move by small teleports, which the mission probably took as leaving the area. So Bon Appetit was not played past that checkpoint, and no other chapter's fight was tried.

Known issues

• Enemies only a friend's game spawned (he got somewhere first) are his alone. The host doesn't see them.
• Mission cars partial: checked in Taxi and Bon Appetit. Where each player starts in his own mission car, the host's character waits hidden until the cars have parted. Handing the car back when the host gets out was not checked. Ambient traffic, pedestrians and police are each player's own.
• Failed missions still take two loads (the stop is confirmed for you if the window has focus). A mission timer running out was not tested.
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels were not tried with a physical gamepad. Steam invites between two different PCs and accounts are not fully tested (joining by IP is the tested route).
• No automatic reconnect after a disconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints
• Your own new character shows once the pause menu closes

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.

MafiaCoop 0.11.0 (pre-release)

Pre-release. Fights are shared properly: a friend's kills count on the host's game, so a friend can clear a fight on his own. Enemies match up again after a reload. Read the known issues before you play.

Download MafiaCoop-0.11.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.11.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone in a session needs 0.11.0. 0.10.x can't join it because the NPC messages changed.

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on mod version 0.11.0; joining by IP needs UDP port 27960 open on the host

New and fixed in 0.11.0

• A friend can win a fight. Before, his game's enemies were kept at 5000 health while the host's lived, so only the host could really kill them. Now their health follows the host's game. A friend's own bullets hurt and kill them on his game, and the host's enemy dies with them: the bullet is replayed on the host's game from the friend's character, and if that misses, the kill is passed on anyway.
  • Checked in Bon Appetit's restaurant fight with two games on one PC: 10 kills by the friend counted on the host's game. With the host not shooting, the friend cleared two attack waves on his own. The host's kills and the damage he deals show on the friend's game.
• Enemies match up again after a reload. After a friend reloaded a checkpoint mid-fight, his enemies no longer matched the host's, because the fight had moved on and only characters at the same spot were matched. Now an enemy that has moved is matched with the nearest one of the same kind within 40 m, and enemies the host already killed die on the friend's game too. Checked: after a friend's reload mid-fight, every enemy matched again (7 of 7 and 8 of 8).
• When the host's checkpoint reloads (failed mission or death), a friend at that checkpoint now reloads it too. Before, the friend's game kept its own fight while the host's started over, and the host's returning enemies shot at him unseen. Checked: the host died mid-fight, the friend reloaded on his own, and all 6 enemies matched.
• Passers-by that took no damage on a friend's game turned out to be characters the game keeps switched off. They are no longer matched with the host's.
• Why the restaurant enemies took no damage in the 0.10.0 test: the mission makes the four attackers in front of the restaurant unhurtable until the player has circled round to them. The attack waves that come round the back can be killed. If a friend's game lets him kill one of those four, the host's dies too.

Tested, not finished

• Bon Appetit's restaurant fight was not played to its end. Its last part waits for a route the automated tests can't walk, so the chapter stopped at that checkpoint. Other chapters' fights were not tried, so NPC sync is still not marked done.

Known issues

• Stay together in fights: each game spawns a fight's later waves when its own player gets there. An enemy that only the host's game has spawned shoots at a friend without showing on the friend's screen.
• Mission cars partial: checked in Taxi and Bon Appetit. Where each player starts in his own mission car, the host's character waits hidden until the cars have parted. Handing the car back when the host gets out was not checked. Ambient traffic, pedestrians and police are each player's own.
• Failed missions still take two loads (the stop is confirmed for you if the window has focus). A mission timer running out was not tested.
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels were not tried with a physical gamepad. Steam invites between two different PCs and accounts are not fully tested (joining by IP is the tested route).
• No automatic reconnect after a disconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints
• Your own new character shows once the pause menu closes

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.

MafiaCoop 0.10.0 (pre-release)

Pre-release. Story fixes after a failed mission, name tags that hide behind walls, and faster detection of a game that was killed. Read the known issues before you play.

Download MafiaCoop-0.10.0.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.10.0-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone in a session needs 0.10.0 (0.9.x cannot join it).

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on mod version 0.10.0; joining by IP needs UDP port 27960 open on the host

New and fixed in 0.10.0

• A reloaded checkpoint starts where it should. The game's chapter loader always put players at the Free Ride start (Salieri's bar), whatever the checkpoint save said. Most checkpoints move you themselves, but Omerta's second one doesn't, so after a failed mission the host stood at the bar and that checkpoint's leave-the-area check never armed. The mod now puts each player where his checkpoint save has him before the mission resumes.
  • Checked with two games on one PC: Omerta's second checkpoint failed and reloaded 8 times by the host (3 with a friend connected) and twice by a friend; Taxi twice each. Always back at the checkpoint's spot, and Omerta's check failed the mission again from every reload.
• One Enter less after a failed mission. The short Free Ride stop on the way back to the checkpoint is now confirmed for you and kept black, so you only see the checkpoint's loading screen (about 20 s after the failure). This works while your game window has focus. Going back in a single load was tried and is not safe (the game then treated the checkpoint as your own story and its fail screen offered your real story save), so the stop stays.
• Losing the mission car fails the mission and goes back to the checkpoint like leaving the area does (checked in Taxi for the host and a friend).
• A friend whose game plays a cutscene of an earlier checkpoint no longer has to sit through it while the host is already further on. In Bon Appetit that was 3 minutes of film. He goes straight to the host's checkpoint.
• Name tags hide behind walls, using the game's own ray cast from the camera to the other player's head.
• A killed or unplugged game is noticed after about 4.5 s (was 10 s). Measured: guest killed, host noticed after 4.6 s; host killed, guest noticed after 4.7 s. A game that is only busy, e.g. loading, is not dropped: a network thread keeps it connected. Setting: net_timeout_s in MafiaCoop.ini (default 4; net_steam_timeout_s 6 over Steam). This is core v0.8.0.
• Fixed a crash of the host's game while loading after a failed mission (with a friend's character in the world). Seen once in Omerta and guarded since; five more failures there ran without a crash.
• Fixed: a friend's name tag could stay hidden for the rest of the session after he was downed. After several reloads in one game the mod could also lose track of most of the world's cars, so mission cars weren't recognised; that's fixed too.

Tested, not finished

• A chapter's own shootout in co-op: Bon Appetit's restaurant ambush was reached through the mission itself. Characters were matched up (11 of 18), enemies fought both players, the host's enemies' hits reached the friend, and deaths were shared. A friend's kill counting on the host could not be checked there: in that phase the enemies took no damage on either game.
• Mission cars in a second chapter: in Bon Appetit the host sits at the wheel of Salieri's car, with Salieri beside him, on a friend's screen. The car being handed back when the host gets out could not be checked, because both chapters tried keep the doors locked.

Known issues

• Shootouts: the enemies on a friend's game only die when the host's do, so a friend alone in a fight cannot win it. A friend's kills in a chapter's own shootout were not checked. Some passers-by take no damage on a friend's game.
• Failed missions still take two loads (the stop is confirmed for you if the window has focus). A mission timer running out was not tested.
• Mission cars partial: checked in Taxi and Bon Appetit. Where each player starts in his own mission car, the host's character waits hidden until the cars have parted. Ambient traffic, pedestrians and police are each player's own.
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels were not tried with a physical gamepad. Steam invites between two different PCs and accounts are not fully tested (joining by IP is the tested route).
• No automatic reconnect after a disconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints
• Your own new character shows once the pause menu closes

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.

MafiaCoop 0.9.1 (pre-release)

Pre-release, a bug-fix release for 0.9.0. If a mission failed in a co-op chapter, the game could load your own story save (another world, outside the co-op game). Read the known issues before you play.

Download MafiaCoop-0.9.1.zip, extract it anywhere (not into the game folder) and run MafiaCoop.exe. The zip's README.txt covers requirements, hosting and joining, settings, the optional start-from-Steam mode and uninstalling. MafiaCoop-0.9.1-symbols.zip holds the PDBs and is only needed to read crash dumps. Everyone in a session needs 0.9.1 (0.9.0 cannot join it).

Requirements

• Windows 10/11, 64-bit
• Mafia: Definitive Edition that you own on Steam, Steam build 16502642 (the current one); Steam running
• Everyone in a session on mod version 0.9.1; joining by IP needs UDP port 27960 open on the host

Fixed in 0.9.1

• A failed mission no longer drops you into your own story. In a co-op CHAPTER (and for a friend in any co-op game), the game answers a failed mission (for example leaving the mission area: "You abandoned the objective") by loading "the free roam state from before the quest", which is a save of your own campaign. In the reported case the host suddenly stood in his real Omerta story, and his game even sent that story's checkpoint on to his friends. Now that load stays inside the co-op game, and as soon as it is up you go back to the last co-op checkpoint (the host to his own, a friend to the host's). Your story saves are never loaded or changed.
  • Checked with two games on one PC: 8 failed missions of the host (Taxi 5 times, one of them with the story save already loaded earlier in that game and one with a friend connected; Omerta 3 times) and 4 of a friend (Taxi 3 times, Omerta in a STORY game once). Each time the player was back at the checkpoint, with no crash.
• Your story slot's data stays untouched. A co-op chapter rewrote the story slot's profile file (aslot.pf: the slot's current chapter and weapons). It now goes to the co-op scratch folder like the saves. Checked: after a two-player chapter with a failed mission on each side, every save and profile file was byte-identical.
• No crash when FREE RIDE is started from the main menu after playing a co-op chapter in the same game.
• The host of a STORY game keeps the game's own "You abandoned the objective" screen (Load Last Checkpoint), since that's his own campaign.

Known issues

• Failed missions take two loads: you first stop briefly in a Free Ride world (press Enter on its loading screen as usual), then the checkpoint loads. Only failing by leaving the mission area was tested. Running out of time and losing a mission car were not.
• After the host reloads Omerta's second checkpoint he starts away from the park, and that checkpoint's leave-the-area check was not active again (seen once in testing, not investigated further)
• Shootouts: enemies aiming at friends was tested with enemies placed by script; no chapter's own big shootout has been played through in co-op yet. Some passers-by take no damage on a friend's game
• Mission cars partial: checked in Taxi only; where each player starts in his own mission car, the host's character waits hidden until the cars have parted; ambient traffic, pedestrians and police are each player's own
• Story co-op tested in a few chapters only (Omerta, Taxi, Bon Appetit and a few chapter starts)
• The co-op panels were not tried with a physical gamepad; Steam invites between two different PCs and accounts are not fully tested (joining by IP is the tested route)
• Name tags show through walls
• A killed game process (instead of a normal close) makes the others wait for a 10 s timeout; no automatic reconnect
• Punches are disabled by the game near Salieri's bar and at some checkpoints
• Your own new character shows once the pause menu closes

Unofficial fan-made mod, not affiliated with 2K, Hangar 13 or Valve. Changes: CHANGELOG.md.