• Fixed the kotlinx-coroutines-debug JAR file including the module-info.class file twice, resulting in failures in various tooling (#4314). Thanks, @RyuNen344!
• Fixed Flow.stateIn hanging when the scope is cancelled in advance or the flow is empty (#4322). Thanks, @francescotescari!
• Improved handling of dispatcher failures in .limitedParallelism (#4330) and during flow collection (#4272).
• Fixed runBlocking failing to run its coroutine to completion in some cases if its JVM thread got interrupted (#4399).
• Small tweaks, fixes, and documentation improvements.

• Fixed binary incompatibility introduced for non-JVM targets in #4261 (#4309).

• Kotlin was updated to 2.1.0 (#4284).
• Introduced Flow.any, Flow.all, and Flow.none (#4212). Thanks, @CLOVIS-AI!
• Reorganized kotlinx-coroutines-debug and kotlinx-coroutines-core code to avoid a split package between the two artifacts (#4247). Note that directly referencing kotlinx.coroutines.debug.AgentPremain must now be replaced with kotlinx.coroutines.debug.internal.AgentPremain. Thanks, @sellmair!
• No longer shade byte-buddy in kotlinx-coroutines-debug, reducing the artifact size and simplifying the build configuration of client code. Thanks, @sellmair!
• Fixed NullPointerException when using Java-deserialized kotlinx-coroutines-core exceptions (#4291). Thanks, @AlexRiedler!
• Properly report exceptions thrown by CoroutineDispatcher.dispatch instead of raising internal errors (#4091). Thanks, @zuevmaxim!
• Fixed a bug that delayed scheduling of a Dispatchers.Default or Dispatchers.IO task after a yield() in rare scenarios (#4248).
• Fixed a bug that prevented the main() coroutine on Wasm/WASI from executing after a delay() call in some scenarios (#4239).
• Fixed scheduling of runBlocking tasks on Kotlin/Native that arrive after the runBlocking block was exited (#4245).
• Fixed some terminal Flow operators sometimes resuming without taking cancellation into account (#4254). Thanks, @jxdabc!
• Fixed a bug on the JVM that caused coroutine-bound ThreadLocal values not to get cleaned when using non-CoroutineDispatcher continuation interceptors (#4296).
• Small tweaks, fixes, and documentation improvements.

Features

• Wasm/WASI target support (#4064). Thanks, @igoriakovlev!
• limitedParallelism now optionally accepts the name of the dispatcher view for easier debugging (#4023).
• No longer initialize Dispatchers.IO on the JVM when other standard dispatchers are accessed (#4166). Thanks, @metalhead8816!
• Introduced the Flow<T>.chunked(size: Int): Flow<List<T>> operator that groups emitted values into groups of the given size (#1290).
• Closeable dispatchers are instances of AutoCloseable now (#4123).

Fixes

• Calling hasNext on a Channel's iterator is idempotent (#4065). Thanks, @gitpaxultek!
• CoroutineScope() created without an explicit dispatcher uses Dispatchers.Default on Native (#4074). Thanks, @whyoleg!
• Fixed a bug that prevented non-Android Dispatchers.Main from initializing when the Firebase dependency is used (#3914).
• Ensured a more intuitive ordering of tasks in runBlocking (#4134).
• Forbid casting a Mutex to Semaphore (#4176).
• Worked around a stack overflow that may occur when calling asDeferred on a Future many times (#4156).

Deprecations and promotions

• Advanced the deprecation levels for BroadcastChannel-based API (#4197).
• Advanced the deprecation levels for the old kotlinx-coroutines-test API (#4198).
• Deprecated Job.cancelFutureOnCompletion (#4173).
• Promoted CoroutineDispatcher.limitedParallelism to stable (#3864).
• Promoted CoroutineStart.ATOMIC from ExperimentalCoroutinesApi to DelicateCoroutinesApi (#4169).
• Promoted CancellableContinuation.resume with an onCancellation lambda to stable, providing extra arguments to the lambda (#4088).
• Marked the classes and interfaces that are not supposed to be inherited from with the new InternalForInheritanceCoroutinesApi opt-in (#3770).
• Marked the classes and interfaces inheriting from which is not stable with the new ExperimentalForInheritanceCoroutinesApi opt-in (#3770).

Other

• Kotlin was updated to 2.0 (#4137).
• Reworked the documentation for CoroutineStart and Channel-based API (#4147, #4148, #4167). Thanks, @globsterg!
• Simplified the internal implementation of Job (#4053).
• Small tweaks, fixes, and documentation improvements.

• Advanced the deprecation levels for BroadcastChannel-based API (#4197).
• Advanced the deprecation levels for the old kotlinx-coroutines-test API (#4198).
• Promoted CoroutineStart.ATOMIC from ExperimentalCoroutinesApi to DelicateCoroutinesApi (#4169).
• Reworked the documentation for CoroutineStart and Channel-based API (#4147, #4148, #4167). Thanks, @globsterg!
• Forbid casting a Mutex to Semaphore (#4176).
• Deprecated Job.cancelFutureOnCompletion (#4156).
• Worked around a stack overflow that may occur when calling asDeferred on a Future many times (#4156).
• Fixed a bug that disallowed setting a custom probeCoroutineResumed when starting coroutines with UNDISPATCHED (#4162).
• No longer initialize Dispatchers.IO on the JVM when other standard dispatchers are accessed (#4166). Thanks, @metalhead8816!
• Small tweaks, fixes, and documentation improvements.

• Kotlin was updated to 2.0 (#4137).
• Introduced the Flow<T>.chunked(size: Int): Flow<List<T>> operator that groups emitted values into groups of the given size (#1290).
• Closeable dispatchers are instances of AutoCloseable now (#4123).
• limitedParallelism now optionally accepts the name of the dispatcher view for easier debugging (#4023).
• Marked the classes and interfaces that are not supposed to be inherited from with the new InternalForInheritanceCoroutinesApi opt-in (#3770).
• Marked the classes and interfaces inheriting from which is not stable with the new ExperimentalForInheritanceCoroutinesApi opt-in (#3770).
• Wasm/WASI target support (#4064). Thanks, @igoriakovlev!
• Promoted CoroutineDispatcher.limitedParallelism to stable (#3864).
• Promoted CancellableContinuation.resume with an onCancellation lambda to stable, providing extra arguments to the lambda (#4088).
• Ensured a more intuitive ordering of tasks in runBlocking (#4134).
• Simplified the internal implementation of Job (#4053).
• Fixed a bug that prevented non-Android Dispatchers.Main from initializing when the Firebase dependency is used (#3914).
• Calling hasNext on a Channel's iterator is idempotent (#4065). Thanks, @gitpaxultek!
• CoroutineScope() created without an explicit dispatcher uses Dispatchers.Default on Native (#4074). Thanks, @whyoleg!
• Small tweaks and documentation fixes.

• Remove the @ExperimentalTime annotation from usages of TimeSource (#4046). Thanks, @hfhbd!
• Introduce a workaround for an Android bug that caused an occasional NullPointerException when setting the StateFlow value on old Android devices (#3820).
• No longer use kotlin.random.Random as part of Dispatchers.Default and Dispatchers.IO initialization (#4051).
• Flow.timeout throws the exception with which the channel was closed (#4071).
• Small tweaks and documentation fixes.

• Remove the @ExperimentalTime annotation from usages of TimeSource (#4046). Thanks, @hfhbd!
• Attempt a workaround for an Android bug that caused an occasional NullPointerException when setting the StateFlow value on old Android devices (#3820).
• No longer use kotlin.random.Random as part of Dispatchers.Default and Dispatchers.IO initialization (#4051).
• Small tweaks.

• Implement the library for the Web Assembly (Wasm) for JavaScript (#3713). Thanks @igoriakovlev!
• Major Kotlin version update: was 1.8.20, became 1.9.21.
• On Android, ensure that Dispatchers.Main != Dispatchers.Main.immediate (#3545, #3963).
• Fixed a bug that caused Flow operators that limit cancel the upstream flow to forget that they were already finished if there is another such operator upstream (#4035, #4038).
• kotlinx-coroutines-debug is published with the correct Java 9 module info (#3944).
• kotlinx-coroutines-debug no longer requires manually setting DebugProbes.enableCoroutineCreationStackTraces to false, it's the default (#3783).
• kotlinx-coroutines-test: set the default timeout of runTest to 60 seconds, added the ability to configure it on the JVM with the kotlinx.coroutines.test.default_timeout=10s (#3800).
• kotlinx-coroutines-test: fixed a bug that could lead to not all uncaught exceptions being reported after some tests failed (#3800).
• delay(Duration) rounds nanoseconds up to whole milliseconds and not down (#3920). Thanks @kevincianfarini!
• Dispatchers.Default and the default thread for background work are guaranteed to use the same context classloader as the object containing it them (#3832).
• It is guaranteed that by the time SharedFlow.collect suspends for the first time, it's registered as a subscriber for that SharedFlow (#3885). Before, it was also true, but not documented.
• Atomicfu version is updated to 0.23.1, and Kotlin/Native atomic transformations are enabled, reducing the footprint of coroutine-heavy code (#3954).
• Added a workaround for miscompilation of withLock on JS (#3881). Thanks @CLOVIS-AI!
• Small tweaks and documentation fixes.

• Fixed a bug introduced in 1.8.0-RC where Mutex.onLock would not unlock if a non-local return was performed (#3985).
• Fixed a bug introduced in 1.8.0-RC where depending on kotlinx-coroutines in Native code failed with a compilation error Could not find "org.jetbrains.kotlinx:atomicfu-cinterop-interop" (#3968).
• Small documentation fixes.