Release Notes

Release Notes

Version history and changelog for LightOS RTOS.

Version 2.3.0 (April 2026)

New Features

• POSIX Timers - Full timer_create/settime/gettime/getoverrun support
• Thread-Local Storage - pthread_key_* APIs with 32 keys per thread
• Spinlocks - pthread_spin_* for interrupt-safe locking
• Thread Naming - pthread_setname_np/getname_np for debugging
• Thread Cancellation - pthread_setcancelstate/setcanceltype
• CPU Affinity - pthread_setaffinity_np for SMP systems

Improvements

• Unit test count increased to 1122
• Documentation updated with 12 new code examples
• RISC-V QEMU demo fixes for scheduler bugs
• Coverage report now at 59.8% line coverage

Bug Fixes

• Fixed RISC-V scheduler context switch
• Fixed thread yield in cooperative mode
• Fixed UART spinlock for output synchronization

Version 2.2.0 (March 2026)

New Features

• RISC-V Port - Full RV64GC support with SMP
• QEMU Support - Run LightOS on QEMU virt machine
• DSP Pipeline - ARM NEON optimized signal processing
• CAN Bus - Controller Area Network driver

Improvements

• 15% faster context switch on Cortex-R52
• Reduced kernel RAM usage by 20%
• New VSCode tasks for build/debug workflow

Version 2.1.0 (February 2026)

New Features

• USB Stack - Device mode with CDC, HID, MSC classes
• FAT Filesystem - FAT12/16/32 support
• Key-Value Store - Persistent storage API

Improvements

• CMake build system overhaul
• Doxygen documentation generation
• GitHub Actions CI/CD pipeline

Version 2.0.0 (January 2026)

Breaking Changes

• Migrated to C++20 (from C++17)
• New namespace structure: lightos::
• Renamed os_* functions to lightos::*

New Features

• SMP Support - Multi-core scheduling
• POSIX Layer - pthread compatibility
• Hypervisor Guest - ARM EL2 support
• SystemView - SEGGER tracing integration

Improvements

• Complete API redesign with modern C++
• Zero-cost abstractions verified
• 1000+ unit tests

Version 1.5.0 (December 2025)

New Features

• MPU Support - Memory protection for Cortex-R
• Tickless Mode - Power-saving idle
• Crash Dump - Post-mortem debugging

Version 1.0.0 (October 2025)

Initial Release

• Priority-based preemptive scheduler
• Mutex, semaphore, queue primitives
• Timer management
• ARM Cortex-R52 support
• Basic memory management

Upgrade Guide

From 1.x to 2.x

1. Update compiler to C++20 compatible
2. Replace os_thread_create → lightos::thread::create
3. Replace os_mutex_* → lightos::mutex
4. Update includes: #include <lightos/lightos.hpp>

From 2.x to 2.3.x

No breaking changes. Optional POSIX features available:

cmake -B build -DLIGHTOS_POSIX_ENABLED=ON