diff --git a/chapter-3/chapter-3-spring-rest-json/pom.xml b/chapter-3/chapter-3-spring-rest-json/pom.xml
index 939aacb8..5e18e424 100644
--- a/chapter-3/chapter-3-spring-rest-json/pom.xml
+++ b/chapter-3/chapter-3-spring-rest-json/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>
diff --git a/chapter-3/chapter-3-spring-webflux-rest-json/pom.xml b/chapter-3/chapter-3-spring-webflux-rest-json/pom.xml
index 09191a9c..f03496b0 100644
--- a/chapter-3/chapter-3-spring-webflux-rest-json/pom.xml
+++ b/chapter-3/chapter-3-spring-webflux-rest-json/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>
diff --git a/chapter-4/chapter-4-spring-data-jpa/pom.xml b/chapter-4/chapter-4-spring-data-jpa/pom.xml
index 44fd748b..434d0f5e 100644
--- a/chapter-4/chapter-4-spring-data-jpa/pom.xml
+++ b/chapter-4/chapter-4-spring-data-jpa/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>
diff --git a/chapter-4/chapter-4-spring-data-r2dbc/pom.xml b/chapter-4/chapter-4-spring-data-r2dbc/pom.xml
index 736c2d8d..b9db21e8 100644
--- a/chapter-4/chapter-4-spring-data-r2dbc/pom.xml
+++ b/chapter-4/chapter-4-spring-data-r2dbc/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>
diff --git a/chapter-5/chapter-5-spring-cloud-events/pom.xml b/chapter-5/chapter-5-spring-cloud-events/pom.xml
index 1c570d1f..84b595e5 100644
--- a/chapter-5/chapter-5-spring-cloud-events/pom.xml
+++ b/chapter-5/chapter-5-spring-cloud-events/pom.xml
@@ -5,7 +5,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>2.7.18</version>
+    <version>4.0.0</version>
     <relativePath />
   </parent>
 
diff --git a/chapter-5/chapter-5-spring-eventbus/pom.xml b/chapter-5/chapter-5-spring-eventbus/pom.xml
index faff85e5..ad4cf43e 100644
--- a/chapter-5/chapter-5-spring-eventbus/pom.xml
+++ b/chapter-5/chapter-5-spring-eventbus/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>
diff --git a/chapter-5/chapter-5-spring-kafka-streams/pom.xml b/chapter-5/chapter-5-spring-kafka-streams/pom.xml
index d4792d28..ebc2b6d2 100644
--- a/chapter-5/chapter-5-spring-kafka-streams/pom.xml
+++ b/chapter-5/chapter-5-spring-kafka-streams/pom.xml
@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.7.18</version>
+		<version>4.0.0</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>org.acme</groupId>