v1.4.20

• XCode 12 support
• Completely reworked escape analysis for object allocation
• Use ForeignException wrapper to handle native exceptions (GH-3553)
• CocoaPods plugin improvements
• equals/hashCode support for adapted callable references (KT-39800)
• equals/hashCode support for fun interfaces (KT-39798)
• IR-level optimizations
  • Constant folding
  • String concatenation flattenning
• Various fixes/improvements to compiler caches
• Some fixes to samples (calculator, tensorflow)
• Bug fixes
  • Eliminate recursive GC calls (KT-42275)
  • Fix support for @OverrideInit constructors with default arguments (KT-41910)
  • Fix support for forward declarations (KT-41655)
  • KT-41394
  • KT-41811
  • KT-41716
  • KT-41250
  • KT-42000
  • KT-41907

Download the binary distribution from https://github.com/JetBrains/kotlin/releases/tag/v1.4.20