CMSIS-RTOS2 API component is maintained with its own versioning that gets offically updated upon releases of the CMSIS Software Pack releases.

The table below provides information about the changes delivered with specific versions of CMSIS-RTOS2 API.

Version	Description
V2.3.0	Changed: OS Tick API moved from Device to CMSIS class Added: Provisional support for processor affinity in SMP systems: osThreadAttr_t :: affinity_mask osThreadSetAffinityMask, osThreadGetAffinityMask
V2.2.0	Added: support for Process Isolation : Kernel Management: osKernelProtect, osKernelDestroyClass Thread Management: osThreadGetClass, osThreadGetZone, osThreadSuspendClass, osThreadResumeClass, osThreadTerminateZone, osThreadFeedWatchdog, osThreadProtectPrivileged Thread attributes: osThreadZone, osThreadUnprivileged, osThreadPrivileged Object attributes: osSafetyClass Handler functions: osWatchdogAlarm_Handler Zone Management: osZoneSetup_Callback Exception Faults: osFaultResume Additional functions allowed to be called from Interrupt Service Routines: osThreadGetName, osEventFlagsGetName, osTimerGetName, osMutexGetName, osSemaphoreGetName, osMemoryPoolGetName, osMessageQueueGetName
V2.1.3	Added: Additional functions allowed to be called from Interrupt Service Routines: osThreadGetId
V2.1.2	Added: Additional functions allowed to be called from Interrupt Service Routines: osKernelGetInfo, osKernelGetState
V2.1.1	Additional functions allowed to be called from Interrupt Service Routines: osKernelGetTickCount, osKernelGetTickFreq Changed Kernel Tick type to uint32_t: updated: osKernelGetTickCount, osDelayUntil
V2.1.0	Support for critical and uncritical sections (nesting safe): updated: osKernelLock, osKernelUnlock added: osKernelRestoreLock Updated Thread Flags and Event Flags: changed flags parameter and return type from int32_t to uint32_t
V2.0.0	New API Version 2.0 available. See CMSIS-RTOS2 API for a detailed function reference.
V1.02 - only documentation changes	Added: Overview of the CMSIS-RTOS Validation Software Pack. Clarified: Behavior of Timeout Values.
V1.02	Added: New control functions for short timeouts in microsecond resolution osKernelSysTick, osKernelSysTickFrequency, osKernelSysTickMicroSec. Removed: osSignalGet.
V1.01	Added: capabilities for C++, kernel initialization and object deletion. Prepared for C++ class interface. In this context to const attribute has been moved from osXxxxDef_t typedefs to the osXxxxDef macros. osTimerDelete, osMutexDelete, osSemaphoreDelete . osKernelInitialize that prepares the kernel for object creation.
V1.00	First official Release. Added: osKernelStart; starting 'main' as a thread is now an optional feature. Semaphores have now the standard behavior. osTimerCreate does no longer start the timer. osTimerStart (replaces osTimerRestart). Changed: osThreadPass is renamed to osThreadYield.
V0.02	Preview Release.