- Compiler performance improvements and fixes for regressions introduced in 1.4.0, including memory, type inference, and stack overflow issues
- Extensive IDE and Gradle integration bug fixes such as editor freezes, REPL errors, project wizard template fixes, and inspection/formatter improvements
- Stability enhancements for Kotlin/Native, KJS/IR, and multiplatform projects addressing cinterop, ObjC export, and build metadata problems