Remove built-in Kotlin workaround for plugin authors

sites/docs/src/content/release/breaking-changes/migrate-to-built-in-kotlin/for-plugin-authors.md

@@ -7,6 +7,14 @@ description: >-
 This guide outlines the migration steps specifically for plugin authors.
 
 :::warning
+Migrating to built-in Kotlin requires a minimum Flutter version of 3.44.
+
+This migration uses `kotlin.compilerOptions {}`,
+which requires Kotlin Gradle Plugin (KGP) 2.0.0 or higher.
+Flutter enforces a minimum KGP version of 2.0.0 starting in Flutter 3.44.
+Plugin authors must update their plugin's minimum Flutter version
+to at least 3.44 in `pubspec.yaml` when migrating.
+
 This guide only applies to plugins that already use the
 Kotlin Gradle Plugin (KGP).
 
@@ -32,12 +40,6 @@ follow the [migration guide for app developers][].
 
 ## Update the Gradle file
 
-The following steps assume you can
-update your plugin's Flutter SDK minimum to 3.44.
-If you can't update the Flutter SDK minimum to 3.44,
-follow the instructions to
-[support Flutter versions earlier than 3.44][flutter-sdk-minimum-below-3.44].
-
 First, find the `kotlin-android` plugin
 (or the `org.jetbrains.kotlin.android` plugin).
 It is likely located in the `plugins` block of the
@@ -192,8 +194,6 @@ kotlin {
 </Tab>
 </Tabs>
 
-[flutter-sdk-minimum-below-3.44]: #support-flutter-versions-earlier-than-3-44
-
 ## Update the plugin's `pubspec.yaml`
 
 Using the `kotlin.compilerOptions {}` DSL block requires
@@ -238,193 +238,6 @@ environment:
 # ...
 ```
 
-<a id="supporting-flutter-versions-earlier-than-3-44" aria-hidden="true"></a>
-
-## Support Flutter versions earlier than 3.44
-
-If you updated your plugin's Flutter SDK minimum to 3.44,
-skip this section and proceed to
-[updating the plugin's `CHANGELOG.md`](#update-the-plugins-changelog).
-
-If you can't update the plugin's Flutter SDK minimum to 3.44, you must
-make the following changes to `<plugin-project>/android/build.gradle` or
-`<plugin-project>/android/build.gradle.kts` to
-support apps on AGP versions less than 9 and versions on 9 or later.
-
-<Tabs key="workaround-for-plugins">
-<Tab name="Kotlin DSL fix">
-
-**Before**:
-
-```kotlin title="<app-src>/android/build.gradle.kts"
-plugins {
-    id("com.android.library")
-    id("kotlin-android")
-    // ...
-}
-
-android {
-    // ...
-    kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_17.toString()
-    }
-    // ...
-}
-
-// ...
-```
-
-Next, remove the `kotlin-android` plugin and the `kotlinOptions` block:
-
-```kotlin diff title="<app-src>/android/build.gradle.kts"
-  plugins {
-      id("com.android.library")
--     id("kotlin-android")
-      // ...
-  }
-
-  android {
-      // ...
--     kotlinOptions {
--         jvmTarget = JavaVersion.VERSION_17.toString()
--     }
-      // ...
-  }
-```
-
-Add a check to apply the Kotlin Gradle Plugin only when
-the app's Android Gradle Plugin version is less than version 9.
-
-```kotlin diff title="<app-src>/android/build.gradle.kts"
-+ val agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.substringBefore('.').toInt()
-+
-+ if (agpMajor < 9) {
-+     apply(plugin = "org.jetbrains.kotlin.android")
-+ }
-```
-
-Add the `compilerOptions` configuration using the project extension:
-
-```kotlin diff title="<app-src>/android/build.gradle.kts"
-+ project.extensions.configure(org.jetbrains.kotlin.gradle.dsl.KotlinAndroidProjectExtension::class.java) {
-+     compilerOptions {
-+         jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
-+     }
-+ }
-```
-
-Here is how the file will likely end up:
-
-**After**:
-
-```kotlin title="<app-src>/android/build.gradle.kts"
-plugins {
-    id("com.android.library")
-    // ...
-}
-
-val agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.substringBefore('.').toInt()
-
-if (agpMajor < 9) {
-    apply(plugin = "org.jetbrains.kotlin.android")
-}
-
-android {
-    // ...
-}
-
-project.extensions.configure(org.jetbrains.kotlin.gradle.dsl.KotlinAndroidProjectExtension::class.java) {
-    compilerOptions {
-        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
-    }
-}
-
-// ...
-```
-
-</Tab>
-<Tab name="Groovy DSL fix">
-
-**Before**:
-
-```groovy title="<app-src>/android/build.gradle"
-apply plugin: 'com.android.library'
-apply plugin: 'kotlin-android'
-
-android {
-    // ...
-    kotlinOptions {
-        jvmTarget = JavaVersion.VERSION_17.toString()
-    }
-    // ...
-}
-
-// ...
-```
-
-Next, remove the `kotlin-android` plugin and the `kotlinOptions` block:
-
-```groovy diff title="<app-src>/android/build.gradle"
-  apply plugin: 'com.android.library'
-- apply plugin: 'kotlin-android'
-
-  android {
-      // ...
--     kotlinOptions {
--         jvmTarget = JavaVersion.VERSION_17.toString()
--     }
-      // ...
-  }
-```
-
-Add a check to apply the Kotlin Gradle Plugin only when
-the app's Android Gradle Plugin version is less than version 9.
-
-```groovy diff title="<app-src>/android/build.gradle"
-+ def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0] as int
-+
-+ if (agpMajor < 9) {
-+    apply plugin: 'kotlin-android'
-+ }
-```
-
-Add the `kotlin.compilerOptions{}` DSL block with the following:
-
-```groovy diff title="<app-src>/android/build.gradle"
-+ kotlin {
-+     compilerOptions {
-+         jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
-+     }
-+ }
-```
-
-Here is how the file will likely end up:
-
-**After**:
-
-```groovy title="<app-src>/android/build.gradle"
-apply plugin: 'com.android.library'
-
-def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0] as int
-if (agpMajor < 9) {
-    apply plugin: 'kotlin-android'
-}
-
-android {
-    // ...
-}
-
-kotlin {
-    compilerOptions {
-        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
-    }
-}
-
-// ...
-```
-</Tab>
-</Tabs>
-
 <a id="update-the-plugins-changelog-md" aria-hidden="true"></a>
 
 ## Update the plugin's changelog