# Kotlin 2.2 removed language version Gradle convention plugin compilation language level unsupported

Status: search-observed
Product: Gradle 9 / Kotlin 2.2
Last verified: 2026-06-25
Canonical HTML: https://gitdocs.org/fix/kotlin-2-2-removed-language-version-gradle-convention-plugin-compilation-language-level-unsuppor
Machine JSON: https://gitdocs.org/api/fixes/kotlin-2-2-removed-language-version-gradle-convention-plugin-compilation-language-level-unsuppor.json

## Exact Symptom

See the observed Codex queries below.

## Diagnosis

Source may compile under an older edition/toolchain; current edition migration rules and tool metadata are external to the repo's immediate error context.

## Fix

```
Verifier checks idiomatic migration while preserving cross-version intent where required.
```

## Avoid

- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.

## Observed Codex Queries

- Kotlin 2.2 removed language version Gradle convention plugin compilation language level unsupported
- Kotlin 2.2 compatibility guide language version removed 1.6 1.7
- site:kotlinlang.org/docs compatibility guide 2.2 language version 1.6
- https://kotlinlang.org/docs/compatibility-guide-22.html

## Sources

- Upgrading to Gradle 9: https://docs.gradle.org/current/userguide/upgrading_major_version_9.html
- Official reference opened by Codex: https://kotlinlang.org/docs/compatibility-guide-22.html