diff --git a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinExtensionTest.java b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinExtensionTest.java
index 6973eb020c..bd1175b992 100644
--- a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinExtensionTest.java
+++ b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinExtensionTest.java
@@ -30,7 +30,7 @@ class KotlinExtensionTest extends GradleIntegrationHarness {
 	void integrationDiktat() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -48,7 +48,7 @@ void integrationDiktat() throws IOException {
 	void integrationKtfmt_dropboxStyle_0_19() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -66,7 +66,7 @@ void integrationKtfmt_dropboxStyle_0_19() throws IOException {
 	void withExperimentalEditorConfigOverride() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -90,7 +90,7 @@ void testWithInvalidEditorConfigFile() throws IOException {
 
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -110,7 +110,7 @@ void testReadCodeStyleFromEditorConfigFile() throws IOException {
 		setFile(".editorconfig").toResource("kotlin/ktlint/ktlint_official/.editorconfig");
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -127,7 +127,7 @@ void testSetEditorConfigCanOverrideEditorConfigFile() throws IOException {
 		setFile(".editorconfig").toResource("kotlin/ktlint/intellij_idea/.editorconfig");
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -145,7 +145,7 @@ void testSetEditorConfigCanOverrideEditorConfigFile() throws IOException {
 	void withCustomRuleSetApply() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -169,7 +169,7 @@ void withCustomRuleSetApply() throws IOException {
 	void testWithHeader() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
@@ -188,7 +188,7 @@ void testWithHeader() throws IOException {
 	void testWithCustomMaxWidthDefaultStyleKtfmt() throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",
diff --git a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinGradleExtensionTest.java b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinGradleExtensionTest.java
index f2b8590083..c607c36912 100644
--- a/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinGradleExtensionTest.java
+++ b/plugin-gradle/src/test/java/com/diffplug/gradle/spotless/KotlinGradleExtensionTest.java
@@ -30,7 +30,7 @@ class KotlinGradleExtensionTest extends KotlinExtensionTest {
 	void testTarget(boolean useDefaultTarget) throws IOException {
 		setFile("build.gradle").toLines(
 				"plugins {",
-				"    id 'org.jetbrains.kotlin.jvm' version '1.5.31'",
+				"    id 'org.jetbrains.kotlin.jvm' version '1.6.21'",
 				"    id 'com.diffplug.spotless'",
 				"}",
 				"repositories { mavenCentral() }",