diff --git a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerGroup.kt b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerGroup.kt
index 6e17176db36..1fa78af5d37 100644
--- a/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerGroup.kt
+++ b/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/internal/CInteropCommonizerGroup.kt
@@ -13,18 +13,17 @@ internal data class CInteropCommonizerGroup(
     @get:Input val targets: Set<SharedCommonizerTarget>,
     @get:Input val interops: Set<CInteropIdentifier>
 ) {
-    @Suppress("deprecation")
     override fun toString(): String {
         return buildString {
-            appendln("InteropsGroup {")
-            appendln("targets: ")
+            appendLine("InteropsGroup {")
+            appendLine("targets: ")
             targets.sortedBy { it.targets.size }.forEach { target ->
-                appendln("    $target")
+                appendLine("    $target")
             }
-            appendln()
-            appendln("interops: ")
+            appendLine()
+            appendLine("interops: ")
             interops.sortedBy { it.toString() }.forEach { interop ->
-                appendln("    $interop")
+                appendLine("    $interop")
             }
             appendLine("}")
         }
diff --git a/libraries/tools/kotlin-maven-plugin-test/src/it/test-kapt-generateKotlinCode/annotation-processor/src/main/kotlin/ExampleAnnotationProcessor.kt b/libraries/tools/kotlin-maven-plugin-test/src/it/test-kapt-generateKotlinCode/annotation-processor/src/main/kotlin/ExampleAnnotationProcessor.kt
index f6e1eb06fb3..f6fbe206d69 100644
--- a/libraries/tools/kotlin-maven-plugin-test/src/it/test-kapt-generateKotlinCode/annotation-processor/src/main/kotlin/ExampleAnnotationProcessor.kt
+++ b/libraries/tools/kotlin-maven-plugin-test/src/it/test-kapt-generateKotlinCode/annotation-processor/src/main/kotlin/ExampleAnnotationProcessor.kt
@@ -31,8 +31,8 @@ class ExampleAnnotationProcessor : AbstractProcessor() {
 
             if (kotlinGenerated != null && element.kind == ElementKind.CLASS) {
                 File(kotlinGenerated, "$simpleName.kt").writer().buffered().use {
-                    it.appendln("package $packageName")
-                    it.appendln("fun $simpleName.customToString() = \"$simpleName: \" + toString()")
+                    it.appendLine("package $packageName")
+                    it.appendLine("fun $simpleName.customToString() = \"$simpleName: \" + toString()")
                 }
             }
         }
diff --git a/libraries/tools/kotlin-maven-plugin-test/src/it/test-kotlin-version-in-manifest/src/main/kotlin/test.kt b/libraries/tools/kotlin-maven-plugin-test/src/it/test-kotlin-version-in-manifest/src/main/kotlin/test.kt
index 89775037357..fce0dd3383a 100644
--- a/libraries/tools/kotlin-maven-plugin-test/src/it/test-kotlin-version-in-manifest/src/main/kotlin/test.kt
+++ b/libraries/tools/kotlin-maven-plugin-test/src/it/test-kotlin-version-in-manifest/src/main/kotlin/test.kt
@@ -54,10 +54,10 @@ fun main(args: Array<String>) {
 
     val uncheckedLibraries = LIBRARIES - implementationTitles
     if (uncheckedLibraries.isNotEmpty()) {
-        errors.appendln("These libraries are not found in the dependencies of this test project, thus their manifests cannot be checked. " +
+        errors.appendLine("These libraries are not found in the dependencies of this test project, thus their manifests cannot be checked. " +
                         "Please ensure they are listed in the <dependencies> section in the corresponding pom.xml:\n$uncheckedLibraries")
-        errors.appendln("(all found libraries: $implementationTitles)")
-        errors.appendln()
+        errors.appendLine("(all found libraries: $implementationTitles)")
+        errors.appendLine()
     }
 
     fun renderEntry(entry: Map.Entry<URL, String?>) = buildString {
@@ -69,16 +69,16 @@ fun main(args: Array<String>) {
 
     val incorrectVersionValues = versionValues.filterValues { it != KOTLIN_VERSION_VALUE }
     if (incorrectVersionValues.isNotEmpty()) {
-        errors.appendln("Manifests at these locations do not have the correct value of the $KOTLIN_VERSION attribute ($KOTLIN_VERSION_VALUE). " +
+        errors.appendLine("Manifests at these locations do not have the correct value of the $KOTLIN_VERSION attribute ($KOTLIN_VERSION_VALUE). " +
                         "Please ensure that kotlin_language_version in libraries/build.gradle corresponds to the value in kotlin.KotlinVersion:")
         incorrectVersionValues.entries.joinTo(errors, "\n", transform = ::renderEntry)
-        errors.appendln()
-        errors.appendln()
+        errors.appendLine()
+        errors.appendLine()
     }
 
     val incorrectRuntimeComponentValues = runtimeComponentValues.filterValues { it != KOTLIN_RUNTIME_COMPONENT_VALUE }
     if (incorrectRuntimeComponentValues.isNotEmpty()) {
-        errors.appendln("Manifests at these locations do not have the correct value of the $KOTLIN_RUNTIME_COMPONENT attribute ($KOTLIN_RUNTIME_COMPONENT_VALUE):")
+        errors.appendLine("Manifests at these locations do not have the correct value of the $KOTLIN_RUNTIME_COMPONENT attribute ($KOTLIN_RUNTIME_COMPONENT_VALUE):")
         incorrectRuntimeComponentValues.entries.joinTo(errors, "\n", transform = ::renderEntry)
     }