Stable Release

Major release: build system migration, extensive security hardening, and disconnect diagnostics.

Build and CI

• Build system migrated from premake to CMake (3.16+). cmake -B build && cmake --build build -j, executables in bin/. See BUILDING.md.
• Full CI: Linux/macOS/Windows debug + release, ASan+UBSan+LSan, MemorySanitizer, bounded fuzzing and a sanitized soak on every PR, plus a nightly extended-fuzzing workflow with a persistent corpus.

Security hardening

• The vendored libsodium is pruned to the used subset, aligned to upstream 1.0.20, and amalgamated into a single header/source pair, with AEAD known-answer tests.
• Five libFuzzer targets cover every untrusted parser, including stateful and structure-aware targets over the connection deserializer. Fuzzing found and fixed: a remote heap overflow in block reassembly, a ChannelPacketData union misread, an uninitialized read of block.messageType, debug-build asserts reachable from the wire, allocation-failure crashes, a network-simulator packet leak, a block fragment-count overflow, and undefined behavior from unaligned bit-reader reads. Regression tests cover each.
• New SECURITY.md with private vulnerability reporting.

New features

• Client/server configuration is validated at startup in debug builds: invalid configs fail loudly with the field name and required value, and compile away entirely in release.
• The server tracks why each client slot was last disconnected: Server::GetClientDisconnectReason(clientIndex) distinguishes kicked, clean disconnect, timed out (via netcode v1.3.2), and specific connection errors (serialize failure, desync, out of memory, …), recorded before OnServerClientDisconnected fires.
• The client reports why it ended up disconnected: Client::GetDisconnectReason() preserves the detailed netcode failure states — connection denied (server full), connect token expired/invalid, request/response/connection timed out, disconnected by server — so games can tell the player what actually happened.
• Insecure connect tokens now use a longer expiry than their timeout, so a failed insecure connect reports "connection request timed out" like a matcher token would.

Vendored libraries

• serialize v1.3.1, reliable v1.3.0, netcode v1.3.2.

Documentation

• USAGE.md: message ownership rules, disconnect reason handling, config validation. README: design assumptions (single-threaded, ~100 players or less, identical client/server config). CONTRIBUTING.md added; BUILDING.md covers CMake and Windows header notes.

Validated with the full CI matrix plus a 5.5-million-iteration soak under AddressSanitizer and UndefinedBehaviorSanitizer at high packet loss, run clean before tagging.

What's Changed

• Fix unaligned dword reads (UB) in BitReader on the packet receive path by @gafferongames in #251
• sodium: prune to used subset, align to 1.0.20, keep all optimized impls, harden, bundle by default by @gafferongames in #252
• sodium: amalgamate bundled libsodium to a single sodium.h + sodium.c (and re-land SIMD/bundle work) by @gafferongames in #253
• Fix network-simulator duplicate-packet leak and block fragment-count overflow by @gafferongames in #254
• Add GitHub Actions CI (Linux, macOS, Windows, sanitizers) by @gafferongames in #255
• README: add CI build status badge by @gafferongames in #256
• Fix minor audit findings (bounds assert, unchecked reassembly alloc, init leak) by @gafferongames in #257
• Remove vestigial SODIUM_STATIC define in yojimbo.cpp by @gafferongames in #258
• Fix return type in hand-declared netcode_enable_packet_tagging prototype by @gafferongames in #259
• yojimbo.cpp: include netcode.h/reliable.h instead of hand-declared prototypes by @gafferongames in #260
• matcher: fix always-true expiry check; safer error/key defaults by @gafferongames in #261
• Add CLAUDE.md working notes and in-progress fuzz harnesses by @gafferongames in #262
• Fuzz the untrusted-input parsers; fix three bugs they found by @gafferongames in #263
• Add time-boxed sanitized soak to CI by @gafferongames in #264
• Add seed corpora for the fuzz targets by @gafferongames in #265
• Add SECURITY.md disclosure policy by @gafferongames in #266
• Add .clang-format encoding the existing house style by @gafferongames in #267
• Add netcode connect-token fuzz target by @gafferongames in #268
• Add richer fuzz seeds: connection-request packet and multi-fragment block by @gafferongames in #269
• USAGE.md: document the mandatory InitializeYojimbo/ShutdownYojimbo by @gafferongames in #270
• Add CONTRIBUTING.md, fix build-doc drift, record a library assessment by @gafferongames in #271
• Fix uninitialized block.message deref on a disabled-blocks channel by @gafferongames in #272
• Make fuzz_connection stateful with config + full-serialize message coverage by @gafferongames in #273
• Add structure-aware fuzz_connection_structured target by @gafferongames in #274
• Add MemorySanitizer CI job (and fix the uninitialized read it found) by @gafferongames in #275
• Add a nightly extended-fuzzing workflow with dictionaries by @gafferongames in #276
• test: print the random seed and allow passing it to reproduce failures by @gafferongames in #278
• Replace premake with CMake by @gafferongames in #277
• CLAUDE.md: the libsodium amalgamation is an agent task, not a missing script by @gafferongames in #279
• Make ChannelPacketData safe by construction: de-union message/block by @gafferongames in #280
• Don't assert on an over-budget packet on the read path (remote DoS) by @gafferongames in #281
• CLAUDE.md: record paused work + public-header encapsulation invariant by @gafferongames in #282
• Fix remote heap overflow in block reassembly and bracketed IPv6 parse by @gafferongames in #283
• Harden read-path message-array allocs and fix network-sim ring draining by @gafferongames in #284
• Harden send-path allocator-exhaustion handling; stop tracking build artifacts by @gafferongames in #285
• Fuzz allocation failures + adversarial block fragments; fix two OOM crashes by @gafferongames in #286
• Fix NULL-client crash in Client::Connect / ConnectLoopback on socket failure by @gafferongames in #287
• Fix NULL-client crash in Client::IsLoopback when disconnected by @gafferongames in #288
• Validate config at startup, document design assumptions, harden .gitignore by @gafferongames in #289
• Add per-client slot disconnect reason to the server by @gafferongames in #290
• Add disconnect reason to the client by @gafferongames in #291
• Document disconnect reasons and config validation by @gafferongames in #292
• Make insecure connect tokens expire like matcher tokens by @gafferongames in #293
• Split server disconnect reason: timed out vs clean disconnect by @gafferongames in #294
• Pre-release cleanups: leak check via assert, no config-sized allocas, loopback kick reason, Windows docs by @gafferongames in #295
• Remove the remaining config-sized allocas from message serialization by @gafferongames in #296
• CLAUDE.md: remove the concerns section — all concerns fully addressed by @gafferongames in #297
• Bump version to 1.5.0 by @gafferongames in #298

Full Changelog: v1.4.0...v1.5.0