Kotlin v2.1.21 released!

NewsBot · 13 May 2025 14:31

Kotlin v2.1.21 has been released.

Changelog

Backend. Native. Debug

KT-75991 Xcode 16.3: Fix lldb stepping test over an inline function

Compiler

KT-75992 Xcode 16.3: stacktraces on simulators are not symbolicated

KT-76663 KJS: KotlinNothingValueException caused by expression return since 2.1.20

KT-75756 Backend Internal error: Exception during IR lowering when trying to access variable from providedProperties in class within kotlin custom script

KT-76209 CONFLICTING_UPPER_BOUNDS on Nothing bound

KT-70352 K2: False-negative CONFLICTING_UPPER_BOUNDS on Nothing bound

KT-74739 Native: “IllegalArgumentException: All constructors should’ve been lowered: FUNCTION_REFERENCE”

KT-75483 Native: redundant unboxing generated with smart cast

KT-71425 IR Inliner: investigate return type of an inlined block

Native

KT-76252 Native: executable crash with generic value classes with 2.1.20

Native. C and ObjC Import

KT-75781 Xcode 16.3: Fix cinterop tests failing with fatal error: could not build module ‘_stdint’

Native. Runtime. Memory

KT-74280 Native: GC.collect crashes with -Xallocator=std

Tools. CLI

KT-75588 [2.1.20-RC] “was compiled by a pre-release version of Kotlin and cannot be loaded by this version of the compiler” warnings despite using the same compiler vers…

Link: Release Kotlin 2.1.21 · JetBrains/kotlin · GitHub