2.0.11 — Co-op Transport Recovery

L4D2MC 2.0.11

Download L4D2MC-Companion.exe, select RU / EN, open Setup and use Update and install on both PCs with Minecraft and L4D2 closed. Launch the Minecraft profile through your normal launcher, then use Play. For co-op, the host creates an invitation and the friend enters their own L4D2 nickname. Installation guide.

This is a normal GitHub release of the EXE and source package. Co-op is still experimental and needs more work. Valid but outdated map mailboxes are discarded without closing the socket. Temporary Windows file contention no longer tears down the room while writing Source mailboxes, collision/session manifests or guest pose/status files: fresh snapshots retry the write. A congested Minecraft mob owner no longer disconnects the player hitting it. Reliable events wait for capacity, preserve order and avoid duplicate accepted damage while camera updates continue. Four new loopback regressions check these failures and recovery on the same socket; the complete Python suite has 151 tests. Genuine network loss and Source stalls can still interrupt play.

Includes the 2.0.10 improvements: hold RMB to revive a downed teammate or help one hanging from a ledge. Downed Steve lies prone, the helper has a two-handed animation and a temporary third-person camera that restores the previous view. Looking away within rescue range keeps use held. Survivor bots can engage hostile Minecraft mobs; Tank attacks send guest knockback and request native punch input.

During rescue, Steve faces the teammate while the camera can turn freely. The action bar uses Source's actual progress timer and is drawn in the final Minecraft GUI layer above Steve.

Known limits: intermittent co-op interruptions, fast-motion reprojection holes, special-infected interactions and incomplete mob abilities. Some grass, bottles and other props can still draw over Minecraft in late Source material passes. A fresh two-PC visual/audio regression is pending; automated tests are not proof of complete gameplay correctness.

Windows 10/11, .NET Framework 4.8, Steam L4D2, Minecraft Java 26.3 / Java 25, official L4D2 Authoring Tools. The EXE is unsigned. Public downloads contain source and companion only; game-derived JAR/HUD, worlds, configs, credentials and toolchains are excluded. SHA-256 files accompany both assets.

2.0.10 — Co-op Recovery & Teammate Rescue

L4D2MC 2.0.10

Download L4D2MC-Companion.exe, select RU / EN, open Setup and use Update and install on both PCs with Minecraft and L4D2 closed. Launch the Minecraft profile through your normal launcher, then use Play. For co-op, the host creates an invitation and the friend enters their own L4D2 nickname. Installation guide.

This is a normal GitHub release of the EXE and source package. Co-op is still experimental and needs more work. Short roster gaps and Source export stalls preserve room membership; stale controls remain disabled. Hold RMB to revive a downed teammate or help one hanging from a ledge. Steve lies down while incapacitated and performs a two-handed help animation while reviving, with an automatic third-person camera that restores the previous view afterward. Looking away within rescue range keeps use held. Survivor bots can engage visible hostile Minecraft mobs while leaving passive mobs and golems alone. Tank attacks send Minecraft mob knockback and request native punch input. Smaller bloom/refraction copies no longer qualify as full-scene composition checkpoints.

During rescue, Steve faces the teammate while the camera can turn freely. The action bar uses Source's actual progress timer and is drawn in the final Minecraft GUI layer above Steve.

Known limits: intermittent co-op interruptions, fast-motion reprojection holes, props/depth ordering on some scenes, special-infected interactions and incomplete mob abilities. A fresh two-PC visual/audio regression is pending; automated tests are not proof of complete gameplay correctness.

Windows 10/11, .NET Framework 4.8, Steam L4D2, Minecraft Java 26.3 / Java 25, official L4D2 Authoring Tools. The EXE is unsigned. Public downloads contain source and companion only; game-derived JAR/HUD, worlds, configs, credentials and toolchains are excluded. SHA-256 files accompany both assets.

2.0.9 Alpha — Setup Test Fix

2.0.9 Alpha — setup test fix

• Setup could stop with FAIL: test_changed_owned_profile_and_other_ids_are_not_replaced (introduced in 2.0.8). The installer again never overwrites your Minecraft launcher profile if you changed it.
• Includes 2.0.8 (updates after playing), 2.0.7 (teammate outline), 2.0.6 (mob damage, corpses, AFK).

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install.

2.0.8 Alpha — Updates After Playing Fixed

2.0.8 Alpha — updates after playing

• Setup failed with Installed file was changed externally: ...\bin\ReShade.ini after you had played once: ReShade saves its own settings into that file. The installer now refreshes the mod's own files anyway and keeps the old copy as *.l4d2mc-previous.
• Includes 2.0.7 (teammate outline only behind walls) and 2.0.6 (mob damage, corpses, no auto-AFK).

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install.

2.0.7 Alpha — Teammate Outline Behind Walls Only

2.0.7 Alpha — teammate outline only behind walls

• The glowing outline around a teammate's Steve now shows only when he is hidden behind walls or props, like L4D2's own teammate outlines. Before, it was always on.
• Includes 2.0.6 (Minecraft mob damage, disappearing corpses, no auto-AFK, setup fix).

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install on both PCs. The outline is computed on the host, so the host's update matters.

2.0.6 Alpha — Mob Damage, Corpses, AFK, Setup Fix

2.0.6 Alpha — mob damage, corpses, AFK, setup fix

• Minecraft mobs now damage survivors. Their hits were silently ignored by L4D2.
• Killed Minecraft mobs disappear instead of lying on the floor forever.
• No more auto-AFK. Leaving AFK needs the shoot button, which belongs to Minecraft, so players got stuck.
• Setup fix: "Build guest jar first" after the 2.0.1 version bump.

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install on both PCs.

2.0.5 Alpha — Invitation Button Fix

2.0.5 Alpha — invitation button fixed

• "Create and copy invitation" did nothing while the game was running. Room buttons (invite, join, solo) now always work, show a confirmation, and apply at the next bridge start. Other buttons tell you why they are unavailable instead of doing nothing.
• Includes 2.0.4 (reinstall fix) and 2.0.3 (crash-safe command channel).

Download the new L4D2MC-Companion.exe below and replace the old one.

2.0.4 Alpha — Install Fix

2.0.4 Alpha — install fix for a previous installation

• Setup failed with Existing unowned file: ...\bin\ReShade.ini if the mod had been installed before from another folder. The installer now recognizes its own previous files and replaces them (the old copy is kept as *.l4d2mc-previous). Other mods' loaders are still never overwritten.
• Includes everything from 2.0.3 (crash-safe command channel, no helper game processes).

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install.

If you still get "No Steam logon" (STEAMAUTH code 8): fully exit Steam and start it again.

2.0.3 Alpha — Crash-safe Command Channel

2.0.3 Alpha — crash-safe command channel, no helper game processes

• Mod commands now run inside L4D2 through the engine's ExecuteClientCmd (verified by disassembling the current engine.dll). The add-on checks the function bytes before every call, so a future L4D2 update cannot crash the game through it.
• No more left4dead2.exe -hijack helper processes: they re-initialized Steam and could invalidate your Steam ticket.
• 2.0.2's fallback is replaced; 2.0.1's crash on start stays fixed.

If you still get "No Steam logon" (STEAMAUTH code 8): fully exit Steam (Steam → Exit) and start it again, then launch. That error is a broken Steam session ticket (Valve Source-1-Games #7758) and survives game restarts. In solo, turn co-op off so the local server runs with sv_lan 1.

Update: close both games, open L4D2MC-Companion.exe → Setup → Update and install on both PCs.

2.0.2 Alpha — L4D2 Crash on Start Fixed

2.0.2 Alpha — L4D2 crash on start fixed

L4D2 closed about a second after the map loaded (crash in tier0.dll, 0xC0000417). The 2.0.1 add-on called an engine function that is not ClientCmd_Unrestricted in the current L4D2 build. Mod configs now go through Source's own -hijack forwarding again, only to an already running L4D2 window, never starting a second copy.

Update: close both games, open L4D2MC-Companion.exe and run Setup → Update and install. Both co-op PCs must update.

Everything else is as in 2.0.1. Validation: 140 Python tests.