diff --git a/spring-cloud-function-context/pom.xml b/spring-cloud-function-context/pom.xml
index 932708a25..881926483 100644
--- a/spring-cloud-function-context/pom.xml
+++ b/spring-cloud-function-context/pom.xml
@@ -47,16 +47,6 @@
 			<artifactId>jackson-module-kotlin</artifactId>
 			<optional>true</optional>
 		</dependency>
-<!--		<dependency> -->
-<!--			<groupId>javax.annotation</groupId>-->
-<!--			<artifactId>javax.annotation-api</artifactId>-->
-<!--			<version>1.3.2</version>-->
-<!--		</dependency>-->
-<!--		<dependency>-->
-<!--		    <groupId>javax.activation</groupId>-->
-<!--		    <artifactId>javax.activation-api</artifactId>-->
-<!--		    <version>1.2.0</version>-->
-<!--		</dependency>-->
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-configuration-processor</artifactId>
@@ -159,15 +149,6 @@
 			<plugin>
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
-				<version>1.6.0</version>
-				<configuration>
-					<args>
-						<arg>-Xjsr305=strict</arg>
-					</args>
-					<compilerPlugins>
-						<plugin>spring</plugin>
-					</compilerPlugins>
-				</configuration>
 				<executions>
 					<execution>
 						<id>compile</id>
@@ -181,26 +162,7 @@
 							</sourceDirs>
 						</configuration>
 					</execution>
-					<execution>
-						<id>test-compile</id>
-						<goals>
-							<goal>test-compile</goal>
-						</goals>
-						<configuration>
-							<sourceDirs>
-								<sourceDir>${project.basedir}/src/test/kotlin</sourceDir>
-								<sourceDir>${project.basedir}/src/test/java</sourceDir>
-							</sourceDirs>
-						</configuration>
-					</execution>
 				</executions>
-				<dependencies>
-					<dependency>
-						<groupId>org.jetbrains.kotlin</groupId>
-						<artifactId>kotlin-maven-allopen</artifactId>
-						<version>1.6.0</version>
-					</dependency>
-				</dependencies>
 			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
diff --git a/spring-cloud-function-kotlin/pom.xml b/spring-cloud-function-kotlin/pom.xml
index a3593575d..f66e686bd 100644
--- a/spring-cloud-function-kotlin/pom.xml
+++ b/spring-cloud-function-kotlin/pom.xml
@@ -64,16 +64,6 @@
 			<plugin>
 				<artifactId>kotlin-maven-plugin</artifactId>
 				<groupId>org.jetbrains.kotlin</groupId>
-				<version>1.8.10</version>
-				<configuration>
-					<args>
-						<arg>-Xjsr305=strict</arg>
-					</args>
-					<compilerPlugins>
-						<plugin>spring</plugin>
-					</compilerPlugins>
-					<jvmTarget>17</jvmTarget>
-				</configuration>
 				<executions>
 					<execution>
 						<id>test-compile</id>
@@ -85,17 +75,9 @@
 								<sourceDir>${project.basedir}/src/test/kotlin</sourceDir>
 								<sourceDir>${project.basedir}/src/test/java</sourceDir>
 							</sourceDirs>
-							<jvmTarget>17</jvmTarget>
 						</configuration>
 					</execution>
 				</executions>
-				<dependencies>
-					<dependency>
-						<groupId>org.jetbrains.kotlin</groupId>
-						<artifactId>kotlin-maven-allopen</artifactId>
-						<version>1.8.10</version>
-					</dependency>
-				</dependencies>
 			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
diff --git a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinLambdasConfiguration.kt b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinLambdasConfiguration.kt
index ef4583d39..a324131fc 100644
--- a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinLambdasConfiguration.kt
+++ b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinLambdasConfiguration.kt
@@ -28,39 +28,39 @@ import java.util.List
  */
 @EnableAutoConfiguration
 @Configuration
-class KotlinLambdasConfiguration {
+open class KotlinLambdasConfiguration {
 
 	@Bean
-	fun uppercase(): Function<String, String> = KotlinComponentFunction()
+	open fun uppercase(): Function<String, String> = KotlinComponentFunction()
 	@Bean
-	fun kotlinFunction(): (String) -> String {
+	open fun kotlinFunction(): (String) -> String {
 		return { it.toUpperCase() }
 	}
 
 	@Bean
-	fun kotlinPojoFunction(): (Person) -> String {
+	open fun kotlinPojoFunction(): (Person) -> String {
 		return { it.name.toString()}
 	}
 	
 	@Bean
-	fun kotlinListPojoFunction(): (List<Person>) -> String {
+	open fun kotlinListPojoFunction(): (List<Person>) -> String {
 		return {
 			"List of: " + it.get(0).name
 		}
 	}
 
 	@Bean
-	fun kotlinConsumer(): (String) -> Unit {
+	open fun kotlinConsumer(): (String) -> Unit {
 		return { println(it) }
 	}
 
 	@Bean
-	fun kotlinSupplier(): () -> String {
+	open fun kotlinSupplier(): () -> String {
 		return { "Hello" }
 	}
 
 	@Bean
-	fun javaFunction(): Function<String, String> {
+	open fun javaFunction(): Function<String, String> {
 		return Function { x -> x }
 	}
 
diff --git a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendFlowLambdasConfiguration.kt b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendFlowLambdasConfiguration.kt
index 937426f9c..bfa7e3102 100644
--- a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendFlowLambdasConfiguration.kt
+++ b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendFlowLambdasConfiguration.kt
@@ -32,32 +32,32 @@ import java.util.function.Function
  */
 @EnableAutoConfiguration
 @Configuration
-class KotlinSuspendFlowLambdasConfiguration {
+open class KotlinSuspendFlowLambdasConfiguration {
 
 	@Bean
-	fun kotlinFunction(): suspend (Flow<String>) -> Flow<String> =  { flow ->
+	open fun kotlinFunction(): suspend (Flow<String>) -> Flow<String> =  { flow ->
 		flow.map { value -> value.toUpperCase() }
 	}
 	
 	@Bean
-	fun kotlinPojoFunction(): suspend (Flow<Person>) -> Flow<String> = { flow ->
+	open fun kotlinPojoFunction(): suspend (Flow<Person>) -> Flow<String> = { flow ->
 		flow.map(Person::toString)
 	}
 
 	@Bean
-	fun kotlinConsumer(): suspend (Flow<String>) -> Unit = { flow ->
+	open fun kotlinConsumer(): suspend (Flow<String>) -> Unit = { flow ->
 		flow.collect(::println)
 	}
 
 	@Bean
-	fun kotlinSupplier(): suspend () -> Flow<String>  = {
+	open fun kotlinSupplier(): suspend () -> Flow<String>  = {
 		flow {
 			emit("Hello")
 		}
 	}
 
 	@Bean
-	fun javaFunction(): Function<Flux<String>, Flux<String>> {
+	open fun javaFunction(): Function<Flux<String>, Flux<String>> {
 		return Function { x -> x }
 	}
 
diff --git a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendLambdasConfiguration.kt b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendLambdasConfiguration.kt
index 66b30bdea..68e985550 100644
--- a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendLambdasConfiguration.kt
+++ b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/KotlinSuspendLambdasConfiguration.kt
@@ -26,20 +26,20 @@ import org.springframework.context.annotation.Configuration
  */
 @EnableAutoConfiguration
 @Configuration
-class KotlinSuspendLambdasConfiguration {
+open class KotlinSuspendLambdasConfiguration {
 
 	@Bean
-	fun kotlinFunction(): suspend (Person) -> String {
+	open fun kotlinFunction(): suspend (Person) -> String {
 		return { it.name.toString()}
 	}
 
 	@Bean
-	fun kotlinConsumer(): suspend (String) -> Unit {
+	open fun kotlinConsumer(): suspend (String) -> Unit {
 		return { println(it) }
 	}
 
 	@Bean
-	fun kotlinSupplier(): suspend () -> String {
+	open fun kotlinSupplier(): suspend () -> String {
 		return { "Hello" }
 	}
 
diff --git a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageSuspendTests.kt b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageSuspendTests.kt
index 3d03ca221..85ad7f68f 100644
--- a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageSuspendTests.kt
+++ b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageSuspendTests.kt
@@ -41,12 +41,12 @@ import java.net.URI
 	properties = ["spring.cloud.function.web.path=/functions", "spring.main.web-application-type=reactive"]
 )
 @ContextConfiguration(classes = [RestApplication::class, HeadersToMessageSuspendTests.TestConfiguration::class])
-class HeadersToMessageSuspendTests {
+open class HeadersToMessageSuspendTests {
 	@Autowired
 	private val rest: TestRestTemplate? = null
 	@Test
 	@Throws(Exception::class)
-	fun testBodyAndCustomHeaderFromMessagePropagation() {
+	open fun testBodyAndCustomHeaderFromMessagePropagation() {
 		// test POJO paylod
 		var postForEntity = rest!!
 			.exchange(
@@ -75,9 +75,9 @@ class HeadersToMessageSuspendTests {
 
 	@EnableAutoConfiguration
 	@org.springframework.boot.test.context.TestConfiguration
-	class TestConfiguration {
+	open class TestConfiguration {
 		@Bean("stringSuspend")
-		fun functiono():suspend (employee: Flow<Message<String>>) -> Flow<Message<String>> = { flow: Flow<Message<String>> ->
+		open fun functiono():suspend (employee: Flow<Message<String>>) -> Flow<Message<String>> = { flow: Flow<Message<String>> ->
 			flow.map { request ->
 				val message =
 					MessageBuilder.withPayload(request.payload)
@@ -88,7 +88,7 @@ class HeadersToMessageSuspendTests {
 		}
 
 		@Bean("employeeSuspend")
-		fun function1(): suspend (employee: Flow<Message<Employee>>) -> Flow<Message<Employee>> = { flow ->
+		open fun function1(): suspend (employee: Flow<Message<Employee>>) -> Flow<Message<Employee>> = { flow ->
 			flow.map { request ->
 				val message =
 					MessageBuilder
@@ -101,7 +101,7 @@ class HeadersToMessageSuspendTests {
 		}
 	}
 
-	class Employee {
+	open class Employee {
 		var name: String? = null
 		var age = 0
 	}
diff --git a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageTests.kt b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageTests.kt
index 894fd7739..02f1c170d 100644
--- a/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageTests.kt
+++ b/spring-cloud-function-kotlin/src/test/kotlin/org/springframework/cloud/function/kotlin/web/HeadersToMessageTests.kt
@@ -41,12 +41,12 @@ import java.net.URI
 	properties = ["spring.cloud.function.web.path=/functions", "spring.main.web-application-type=reactive"]
 )
 @ContextConfiguration(classes = [RestApplication::class, HeadersToMessageTests.TestConfiguration::class])
-class HeadersToMessageTests {
+open class HeadersToMessageTests {
 	@Autowired
 	private val rest: TestRestTemplate? = null
 	@Test
 	@Throws(Exception::class)
-	fun testBodyAndCustomHeaderFromMessagePropagation() {
+	open fun testBodyAndCustomHeaderFromMessagePropagation() {
 		// test POJO paylod
 		var postForEntity = rest!!
 			.exchange(
@@ -74,9 +74,9 @@ class HeadersToMessageTests {
 
 	@EnableAutoConfiguration
 	@org.springframework.boot.test.context.TestConfiguration
-	class TestConfiguration {
+	open class TestConfiguration {
 		@Bean("string")
-		fun functiono(): (message: Message<String?>) -> Message<String> = { request: Message<String?> ->
+		open fun functiono(): (message: Message<String?>) -> Message<String?> = { request: Message<String?> ->
 			val message =
 				MessageBuilder.withPayload(request.payload)
 					.setHeader("X-Content-Type", "application/xml")
@@ -85,7 +85,7 @@ class HeadersToMessageTests {
 		}
 
 		@Bean("employee")
-		fun function1(): (employee: Message<Employee>) -> Message<Employee> = { request ->
+		open fun function1(): (employee: Message<Employee>) -> Message<Employee> = { request ->
 			val message =
 				MessageBuilder
 					.withPayload(request.payload)
@@ -96,7 +96,7 @@ class HeadersToMessageTests {
 	}
 
 	// used by json converter
-	class Employee {
+	open class Employee {
 		var name: String? = null
 		var age = 0
 	}
diff --git a/spring-cloud-function-samples/function-sample-kotlin-web/pom.xml b/spring-cloud-function-samples/function-sample-kotlin-web/pom.xml
index f5f668f5b..fdd0943cc 100644
--- a/spring-cloud-function-samples/function-sample-kotlin-web/pom.xml
+++ b/spring-cloud-function-samples/function-sample-kotlin-web/pom.xml
@@ -84,7 +84,7 @@
 					<dependency>
 						<groupId>org.jetbrains.kotlin</groupId>
 						<artifactId>kotlin-maven-allopen</artifactId>
-						<version>1.8.10</version>
+						<version>${kotlin.version}</version>
 					</dependency>
 				</dependencies>
 			</plugin>