Legacy vs Enhanced

A single reference for everything that changed between FiveM Legacy (Gen8) and FiveM Enhanced (Gen9). These are the developer- and server-facing changes that break resources or server.cfg files during migration. Based on the official What's Changed documentation.

Server binaries

Runtimes

• Mono → .NET. C# resources now require a .NET 10 SDK and must be rebuilt. (Secondary sources also cite NodeJS 26 and V8 14.6; only .NET 10 is confirmed by the primary docs.)
• Lua 5.3 removed (June 2025) — every resource's fxmanifest.lua must contain lua54 'yes'.

Networking & sync

• P2P synchronization removed — Enhanced uses a client-server model only.
• OneSync "big mode" is the only mode — non-big mode is gone.
• Sync tick rate is configurable up to 120 Hz (see sv_syncTickRate below).
• ARQ / onesync_automaticResend removed.
• endpoint_add_tcp / endpoint_add_udp now support only a single endpoint each (not multiple).

Convars — changed, deprecated & removed

• sv_syncTickRate — tick rate for the sync thread. Default 60, range 1–120. Higher reduces latency but increases CPU usage.
• sv_entityLockdown — modes include full (disables dummy object creation) and relaxed (restricts population spawning to a player-owned world grid).
• sv_resourceFileDownloadTimeout — per-file resource download timeout in milliseconds (default 2 minutes).
• sv_devMode true — enables developer tools server-wide; limited to eight player slots to prevent production use. (Docs write sv_devMode; the forum uses sv_devmode.)

Removed developer tooling

• DevCon ports 29200 and 29300 removed.
• Server-side ImGui GUI removed.
• -cl2 client launch parameter deprecated.
• Resources can no longer be builders (the resource-builder / build-step pattern was removed).
• Remote commands no longer return the full log to the client — call PrintRemoteCommandLog(message) explicitly.

Pure Mode & graphics

• Pure Mode is now always enabled and can no longer be turned off.
• While Enhanced is in early access, graphic mods cannot be used. (Ray tracing / modern rendering come from the GTA V Enhanced game build itself.)

Asset Escrow

• Not implemented yet in early access. Escrow-protected (encrypted) resources cannot be relied upon. Cfx.re advises most production servers to wait for this feature before migrating.

State bags & replication

• Callbacks only fire if the entity exists.
• Replicated values are only replicated if explicitly set. (In Legacy, server-set state replicated by default — code that relied on implicit replication must now set it explicitly.)

Voice (Mumble)

• Mumble is deprecated. The Mumble natives still function only because they route through the new voice system, and will be removed in a future version.
• Migrate to the new server-side Voice API — see docs.fivem.net/docs/scripting-manual/voice.
• Community voice/radio resources (e.g. pma-voice) currently keep working only because of that temporary routing. Plan a migration.

Gamebuild

• Only the latest gamebuild (Kortz Center Heist) is supported. Use sv_enforceGameBuild 1 for the base game without DLCs. Older pins (2802 / 3095 / 3258…) will hit "invalid game build enforcement." Set enforcement in the startup command, after +exec server.cfg.

Database

• Key-Value (KVP) database files must be migrated with the official migration script. Do not point Enhanced at a live production database — clone it first.