Install Fabric
Install Fabric Loader for Minecraft 1.21.11, then add the matching Fabric API to your mods folder.
Current build: Terrified Client v1.6.6 for Minecraft 1.21.11.
Install Fabric Loader for Minecraft 1.21.11, then add the matching Fabric API to your mods folder.
Download the latest JAR and place it inside .minecraft/mods. Keep only one Terrified Client JAR installed.
Launch Minecraft. Enter the license key you purchased through Discord. The key is remembered and bound to that PC's HWID.