Downgrade to Kotlin 2.0.21

compiler-plugin/src/test/kotlin/com/google/devtools/ksp/test/AbstractKSPTest.kt

@@ -185,7 +185,7 @@ abstract class AbstractKSPTest(frontend: FrontendKind<*>) : DisposableTest() {
             "-classpath", classpath,
             "-d", module.outDir.path
         )
-        compileJavaFiles(javaFiles, options)
+        compileJavaFiles(javaFiles, options, assertions = JUnit5Assertions)
     }
 
     fun runTest(@TestDataFile path: String) {

gradle-plugin/src/main/kotlin/com/google/devtools/ksp/gradle/KotlinFactories.kt

@@ -166,7 +166,7 @@ class KotlinFactories {
                         from = compilerOptions,
                         into = kspTask.compilerOptions
                     )
-                    kspTask.produceUnpackagedKlib.set(false)
+                    kspTask.produceUnpackedKlib.set(false)
                     kspTask.onlyIf {
                         // KonanTarget is not properly serializable, hence we should check by name
                         // see https://youtrack.jetbrains.com/issue/KT-61657.

gradle-plugin/src/main/kotlin/com/google/devtools/ksp/gradle/KspSubplugin.kt

@@ -417,6 +417,7 @@ class KspGradleSubplugin @Inject internal constructor(private val registry: Tool
         }
 
         fun configureLanguageVersion(kspTask: KotlinCompilationTask<*>) {
+            kspTask.compilerOptions.useK2.value(false)
             val languageVersion = kotlinCompilation.compilerOptions.options.languageVersion
             val progressiveMode = kotlinCompilation.compilerOptions.options.progressiveMode
             kspTask.compilerOptions.languageVersion.value(

gradle.properties

@@ -1,10 +1,10 @@
 # Copied from kotlinc
 org.gradle.jvmargs=-Duser.country=US -Dkotlin.daemon.jvm.options=-Xmx4096m -Dfile.encoding=UTF-8
 
-kotlinBaseVersion=2.1.20-dev-3305
+kotlinBaseVersion=2.0.21
 agpBaseVersion=7.3.1
 agpTestVersion=8.7.1
-intellijVersion=233.13135.128
+intellijVersion=233.13135.103
 junitVersion=4.13.1
 junit5Version=5.8.2
 junitPlatformVersion=1.8.2