MPFever 0.5.5

Fewer reloads: after a replayed build, every game gives new vehicles and buildings the same ids. Train stations no longer slow the game down without a lobby.

MPFever is still in active development: back up your savegames.

Two archives

• MPFever-0.5.5.zip: for players.
• MPFever-0.5.5-server.zip: the same, plus what a dedicated server needs (start-server.bat, SERVER.txt).

MPFever 0.3.15 and later update themselves to 0.5.5 when the game closes. Every player needs the same version.

Fixes

• Towns and vehicles drifting apart after a build, then a reload. This was the most frequent cause of reloads in our testers' sessions of 2026-10-25 (4 reloads out of 6). Every new vehicle, building or road piece takes its id from a queue of free ids kept by the game. Replaying another player's build, for example a bus stop or a bus terminal, could leave that queue in another order on one game only. From then on, every new entity got another id there: in one session, the next vehicle bought was number 350772 on one game and 353349 on the other. Towns and vehicles then slowly went apart until the games reloaded. MPFever now keeps that queue in order, so every game gives the same ids. Measured at x4 with two games on one PC: no speed cost (x3.93 against x3.96).
• Reloads for nothing. The check added in 0.5.3 that compares the ids of each build could read them at a different moment on each game when the game ran faster than x1. One session reloaded although both games were the same. That check is now only written to the log, and never triggers a reload.
• The frame rate fell with every module added to a train station (issue #82), when the game ran without a lobby (MPFever.exe, then a savegame loaded from the game's own menu). MPFever kept a full copy of every build to send it to the other players, and without a lobby nobody took it. The game copies that data several times per frame. Measured on a train station of 31 modules edited 6 times: the frame rate went from 78 to 43 fps. Without a lobby, MPFever now keeps nothing. In a lobby, 0.5.3 already dropped the copies once sent: the frame rate stayed between 84 and 88 fps.
• Building stopped working after a session (issue #82): back in the main menu, then a savegame loaded from the game's menu, a new build could stay waiting forever. MPFever no longer holds builds once the session is over.

Diagnostics

• Two builds of another player were built two steps after their time on one game, which led to a reload. MPFever now writes in its log how the game stands when it replays a build, to find the cause if it happens again. In a later 50-minute session, all 100 replayed builds were built at their exact time.

Checked

• Desyncs: two games on one PC with BUILDLEAD on. Each player places bus stops on town streets, builds new roads and buys vehicles, then the game runs 3 minutes at x4: in sync, and both games gave every build and every vehicle the same ids.
• A real session of 50 minutes with the new id queue (our testers, 2 PCs): no crash, the queue was kept in order 470,000 times without a single failure.
• Train station: the frame rate measurements above.
• Joining through Steam between two Steam accounts on two PCs (new in 0.5.3, not tested at the time) works in real sessions: the host's game (23 to 29 MB of differences at each reload) was sent over 4 Steam connections in 3 to 18 s.

Known issues

• Many bus stops placed or removed in a pause, then vehicles bought: the games can still give the new vehicles different ids, and reload a few minutes later. Replaying a bus stop does not always create exactly what the stop tool created. This is the next fix we are working on.
• Disabling MPFever while still in a lobby, then loading a savegame, still blocks building: leave the lobby first.

If you enjoy MPFever, you can support it on Ko-fi, or leave a comment or a like on Nexus.

Files:

• MPFever-0.5.5.zip, SHA-256 B1FEF60D9C6D1D546255506954A84BBFB04EFE91E35E01C0B65341DE373C67D5
• MPFever-0.5.5-server.zip, SHA-256 7CA2CF5F293C556445ED388F9D129785CF3B293A9EBE2351DC0A973FC8C5562A