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Nov 13, 2025
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Remove language versions in compatibility guide for 2.2.0 #5148

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17 changes: 17 additions & 0 deletions docs/topics/compatibility-guides/compatibility-guide-22.md
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Expand Up @@ -23,6 +23,23 @@ perspective (for example, from Java) is out of the scope of this document.

## Language

### Drop support in `-language-version` for 1.6 and 1.7

> **Issue**: [KT-71793](https://youtrack.jetbrains.com/issue/KT-71793)
>
> **Component**: Compiler
>
> **Incompatible change type**: source
>
> **Short summary**: Starting with Kotlin 2.2, the compiler no longer supports [`-language-version=1.6`](compiler-reference.md#language-version-version) or `-language-version=1.7`.
> This means that language feature sets older than 1.8 are no longer supported. However, the language itself remains
> fully backward compatible with Kotlin 1.0.
>
> **Deprecation cycle**:
>
> - 2.1.0: report a warning when using `-language-version` with versions 1.6 and 1.7
> - 2.2.0: report a warning when using `-language-version` with versions 1.8 and 1.9; raise the warning to an error for versions 1.6 and 1.7

### Enable invokedynamic for annotated lambdas by default

> **Issue**: [KTLC-278](https://youtrack.jetbrains.com/issue/KTLC-278)
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4 changes: 3 additions & 1 deletion docs/topics/compiler-reference.md
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Expand Up @@ -84,7 +84,9 @@ Core plugins and their options are listed in the [Core compiler plugins](compone

### -language-version _version_

Provide source compatibility with the specified version of Kotlin.
This option sets the supported syntax and semantics according to the specified language version. For example, using
Kotlin compiler version 2.2.0 with `-language-version=1.9` lets you use only the language features and standard library APIs from
version 1.9 or earlier. This can help with a gradual migration to newer Kotlin versions.

### -api-version _version_

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17 changes: 6 additions & 11 deletions docs/topics/whatsnew/whatsnew22.md
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Expand Up @@ -1319,8 +1319,11 @@ If you encounter any issues that make you disable these feature flags, please re
This section highlights important breaking changes and deprecations worth noting. See our [Compatibility guide](compatibility-guide-22.md)
for a complete overview of all breaking changes and deprecations in this release.

* Starting with Kotlin 2.2.0, support for the [](ant.md) build system is deprecated. Kotlin support for Ant hasn't been
in active development for a long time, and there are no plans to maintain it further due to its relatively small user base.
* Starting with Kotlin 2.2.0, the compiler [no longer supports `-language-version=1.6` or `-language-version=1.7`](compatibility-guide-22.md#drop-support-in-language-version-for-1-6-and-1-7).
Language feature sets older than 1.8 aren't supported but the language itself remains fully backward compatible with Kotlin 1.0.

* Support for the [](ant.md) build system is deprecated. Kotlin support for Ant hasn't been in active development for a
long time, and there are no plans to maintain it further due to its relatively small user base.

We plan to remove Ant support in 2.3.0. However, Kotlin remains open to [contribution](contribute.md). If you're
interested in becoming an external maintainer for Ant, leave a comment with the "jetbrains-team" visibility setting in [this YouTrack issue](https://youtrack.jetbrains.com/issue/KT-75875/).
Expand Down Expand Up @@ -1364,15 +1367,7 @@ for a complete overview of all breaking changes and deprecations in this release

This release brings notable documentation changes, including the migration of Kotlin Multiplatform documentation to the [KMP portal](https://kotlinlang.org/docs/multiplatform/get-started.html).

Additionally, we launched a documentation survey, created new pages and tutorials, and revamped existing ones.

### Kotlin's documentation survey

We're looking for genuine feedback to make the Kotlin documentation better.

The survey takes around 15 minutes to complete, and your input will help shape the future of Kotlin docs.

[Take the survey here](https://surveys.jetbrains.com/s3/Kotlin-Docs-2025).
Additionally, we created new pages and tutorials, and revamped existing ones.

### New and revamped tutorials

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