diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index 6854a96..f3a3d7c 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -16,7 +16,7 @@ jobs:
     - name: Set up Java
       uses: actions/setup-java@v3
       with:
-        java-version: '21'
+        java-version: '17'
         distribution: 'temurin'
     - name: Gradle cache
       uses: actions/cache@v3
diff --git a/README.md b/README.md
index db2ca99..8c44944 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
 ![CI](https://github.com/rogervinas/spring-cloud-stream-kafka-step-by-step/actions/workflows/gradle.yml/badge.svg)
-![Java](https://img.shields.io/badge/Java-21-blue?labelColor=black)
+![Java](https://img.shields.io/badge/Java-17-blue?labelColor=black)
 ![Kotlin](https://img.shields.io/badge/Kotlin-1.9.21-blue?labelColor=black)
-![SpringBoot](https://img.shields.io/badge/SpringBoot-3.2.0-blue?labelColor=black)
-![SpringCloud](https://img.shields.io/badge/SpringCloud-2023.0.0_RC1-blue?labelColor=black)
+![SpringBoot](https://img.shields.io/badge/SpringBoot-2.7.8-blue?labelColor=black)
+![SpringCloud](https://img.shields.io/badge/SpringCloud-2021.0.8-blue?labelColor=black)
 
 # Spring Cloud Stream & Kafka binder step by step
 
diff --git a/build.gradle.kts b/build.gradle.kts
index e62334c..9b99f97 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -3,23 +3,22 @@ import org.gradle.api.tasks.testing.logging.TestLogEvent.*
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
 
 plugins {
-  id("org.springframework.boot") version "3.2.0"
-  id("io.spring.dependency-management") version "1.1.4"
+  id("org.springframework.boot") version "2.7.18"
+  id("io.spring.dependency-management") version "1.0.15.RELEASE"
   kotlin("jvm") version "1.9.21"
   kotlin("plugin.spring") version "1.9.21"
 }
 
 group = "com.rogervinas"
 version = "0.0.1-SNAPSHOT"
-java.sourceCompatibility = JavaVersion.VERSION_21
-java.targetCompatibility = JavaVersion.VERSION_21
+java.sourceCompatibility = JavaVersion.VERSION_17
+java.targetCompatibility = JavaVersion.VERSION_17
 
 repositories {
 	mavenCentral()
-  maven { url = uri("https://repo.spring.io/milestone") }
 }
 
-val springCloudVersion = "2023.0.0-RC1"
+val springCloudVersion = "2021.0.8"
 
 dependencies {
 	implementation("org.springframework.boot:spring-boot-starter-web")
@@ -45,7 +44,7 @@ dependencyManagement {
 tasks.withType<KotlinCompile> {
 	kotlinOptions {
 		freeCompilerArgs = listOf("-Xjsr305=strict")
-		jvmTarget = "21"
+		jvmTarget = "17"
 	}
 }
 
diff --git a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
index 12d69d0..0f98a18 100644
--- a/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
+++ b/src/main/kotlin/com/rogervinas/stream/functional/MyStreamEventProducer.kt
@@ -17,7 +17,7 @@ class MyStreamEventProducer : () -> Flux<Message<MyEventPayload>>, MyEventProduc
   override fun produce(event: MyEvent) {
     val message = MessageBuilder
       .withPayload(toPayload(event))
-      .setHeader(KafkaHeaders.KEY, toKey(event))
+      .setHeader(KafkaHeaders.MESSAGE_KEY, toKey(event))
       .build()
     sink.emitNext(message, FAIL_FAST)
   }
diff --git a/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt b/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
index 8f270b6..d80ca56 100644
--- a/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
+++ b/src/main/kotlin/com/rogervinas/stream/shared/MyContainers.kt
@@ -1,12 +1,12 @@
 package com.rogervinas.stream.shared
 
-import jakarta.annotation.PostConstruct
-import jakarta.annotation.PreDestroy
 import org.springframework.context.annotation.Profile
 import org.springframework.stereotype.Component
 import org.testcontainers.containers.ComposeContainer
 import org.testcontainers.containers.wait.strategy.Wait.forLogMessage
 import java.io.File
+import javax.annotation.PostConstruct
+import javax.annotation.PreDestroy
 
 @Component
 @Profile("docker-compose")