Krypton Reno

What Krypton Reno does Krypton Reno is a network-focused optimization mod ported from the Fabric-side Krypton project. It targets the connection layer on both client and server, applying mixin-level changes to reduce allocation, lock contention, and unnecessary packets. The mod runs on NeoForge and Forge. It supports Minecraft 1.20.1 and the 1.21.x line (listed as 26.1, 26.1.1, 26.1.2, 26.2). Both client and server installs are optional; you can run it on one side only. ## Native acceleration on Windows The standout addition over upstream Krypton is RecastLib, a Rust-written native library that ships with the mod. On Windows x64 and arm64 it replaces portions of the Netty pipeline with JNI bindings, giving lower-level throughput gains that pure-Java mixins can't reach. Linux and macOS users don't get RecastLib; those platforms rely on Velocity Native instead, which the author notes is mutually exclusive with RecastLib. There's no support for Android, 32-bit architectures, or other platforms. ## Configurable mixin toggles Most optimizations live behind a YAML config under the mixin key. Each toggle decides whether a specific mixin is applied at startup, so changes require a restart. Highlights include bestVarLong for a faster VarLong implementation, clientEncrypt for client-side encryption fast-paths, trackedEntityOpt to reduce allocations when broadcasting entity packets, and particlePacketOpt to drop redundant particle packets on the server. Virtual-thread replacements for text filtering and download threads are also available (textFilterVT, utilVT). A separate culling section lets servers hide occluded display and hanging entities without removing gameplay entities. ## Compatibility notes Forge support ended at the 26.1 line; current releases target NeoForge only. The mod declares a mandatory dependency on Spring Lotus (LibSL) starting with the 26.3 series, used to share boilerplate across the author's other mods. Happy Eyeballs (RFC 8305) for dual-stack client connections is present but off by default (happyEyeballs: false) because it can cause temporary connection refusals on some Velocity proxies. Compression level, oversized-packet handling, and a custom OreUI replacement are also configurable.