Offline Mode Fix

# Offline Mode Fix > > Active development and source code for this project are hosted on (https://codeberg.org/louiszn/offline-mode-fix). > > If you are reading this on another platform, you are viewing a read-only mirror. Please open all issues, pull requests on the official Codeberg repository. ## About A lightweight, plug-and-play Fabric mod that fixes several client-side issues commonly encountered when playing on offline-mode Minecraft servers. It reduces chat-related network delays, cleans up insecure chat indicators, restores player heads in the tab list, suppresses the unverified-server warning, and improves compatibility with malformed texture signatures used by some offline skin systems. ## Features * **Reduced Chat Lag:** Bypasses unnecessary player blocklist checks for offline-mode UUIDs and disables client-side text filtering checks that may depend on account services. * **Offline Login Fixes:** Skips multiplayer account-service preparation when the local player is using a Version 3 offline-mode UUID, preventing unnecessary authentication requests and related errors. * **Clean Chat UI:** Removes chat message sidebar tags, including the red and gray "Not Secure" indicators shown on unsigned messages. * **Player Heads:** Restores player head rendering in the multiplayer player list. * **No Annoying Toasts:** Hides the "Unverified Server" warning shown when joining insecure or offline-mode servers. * **Better Offline Skin Compatibility:** Bypasses strict texture signature validation for known malformed dummy signature formats used by some offline skin systems. * **Premium-Friendly:** The offline-specific multiplayer preparation bypass is only enabled when the local account uses an offline-mode UUID, so the mod can remain installed while joining online-mode servers. > > Some client-side tweaks, such as hiding chat tags, disabling text filtering, restoring tab-list heads, and suppressing the unverified-server warning, remain active regardless of account type. Installing the mod therefore does not preserve completely vanilla client behavior on online-mode servers. ## Installation 1. Install Fabric Loader for your Minecraft version. 2. Download the correct `.jar` for your Minecraft version from the official (https://modrinth.com/mod/offline-mode-fix) page. 3. Place the `.jar` in your `.minecraft/mods` folder. 4. Launch the game using your Fabric profile. No server-side installation is required for the fixes themselves. ## Building from Source This project uses (https://stonecutter.kikugie.dev/) to support multiple Minecraft versions from a single codebase. You will need: * Java 25 or newer * Git ### 1. Clone the repository ```bash git clone https://github.com/louiszn/offline-mode-fix cd offline-mode-fix ``` ### 2. Build all supported versions On Linux or macOS: ```bash ./gradlew buildAndCollect ``` On Windows: ```powershell gradlew buildAndCollect ``` Individual version builds can also be run through their corresponding Gradle projects. Compiled `.jar` files can be found under: ```text versions/<minecraft-version>/build/libs/ ``` ## IDE Setup ### IntelliJ IDEA Because Stonecutter uses preprocessing directives to maintain multiple Minecraft versions in one codebase, installing the **Stonecutter Dev** plugin by KikuGie is recommended for proper syntax highlighting and code analysis. To switch the active development version: 1. Open the Gradle tool window. 2. Navigate to `Tasks -> stonecutter`. 3. Run the corresponding `Set active project to ...` task. For example, selecting the `1.21.11` project makes that version active in the IDE. ## How It Works Offline-mode servers can expose several client behaviors that normally assume players and servers are backed by Mojang account services. Offline Mode Fix applies a small set of Mixins to change those behaviors. ### Player blocklist checks Minecraft normally calls `isBlocked(UUID)` when processing players and chat messages. For: * `null` UUIDs, * Version 3 UUIDs used by offline-mode players, and * the NIL UUID used by system messages, the mod immediately returns `false` instead of performing the normal blocklist check. Premium UUIDs continue through the vanilla `isBlocked` implementation. ### Text filtering The mod overrides `isTextFilteringEnabled()` and returns `false`. This disables the client-side text filtering path and avoids account-service-dependent filtering checks. This behavior is currently applied regardless of whether the local account is offline or authenticated. ### Multiplayer preparation When joining multiplayer, Minecraft normally runs `prepareForMultiplayer()`, which initializes account-dependent multiplayer services. The mod checks the local player's profile UUID before changing this behavior. If the local profile uses a Version 3 offline-mode UUID, the preparation step is cancelled. Authenticated accounts continue through the normal vanilla mul