diff --git a/build.gradle b/build.gradle
index 401094108..ea2322320 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,7 +1,7 @@
 plugins {
   id 'java'
   id 'checkstyle'
-  id 'org.springframework.boot' version '3.5.6'
+  id 'org.springframework.boot' version '3.5.0'
   id 'io.spring.dependency-management' version '1.1.7'
   id 'org.graalvm.buildtools.native' version '0.11.1'
   id 'org.cyclonedx.bom' version '3.0.0'
@@ -12,7 +12,7 @@ plugins {
 gradle.startParameter.excludedTaskNames += [ "checkFormatAot", "checkFormatAotTest" ]
 
 group = 'org.springframework.samples'
-version = '3.5.0'
+version = '4.0.0-SNAPSHOT'
 
 java {
   toolchain {
@@ -48,6 +48,7 @@ dependencies {
   runtimeOnly 'org.postgresql:postgresql'
   developmentOnly 'org.springframework.boot:spring-boot-devtools'
   testImplementation 'org.springframework.boot:spring-boot-starter-test'
+  testImplementation 'org.springframework.boot:spring-boot-starter-restclient'
   testImplementation 'org.springframework.boot:spring-boot-testcontainers'
   testImplementation 'org.springframework.boot:spring-boot-docker-compose'
   testImplementation 'org.testcontainers:junit-jupiter'
diff --git a/pom.xml b/pom.xml
index 004709a9b..08367b32e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,13 +5,13 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.6</version>
+    <version>4.0.0-M2</version>
     <relativePath></relativePath>
   </parent>
 
   <groupId>org.springframework.samples</groupId>
   <artifactId>spring-petclinic</artifactId>
-  <version>3.5.0-SNAPSHOT</version>
+  <version>4.0.0-SNAPSHOT</version>
 
   <name>petclinic</name>
 
@@ -69,6 +69,10 @@
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
+    </dependency>    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-restclient</artifactId>
+      <scope>test</scope>
     </dependency>
 
     <!-- Databases - Uses H2 by default -->
@@ -288,43 +292,6 @@
     </license>
   </licenses>
 
-  <repositories>
-    <repository>
-      <snapshots>
-        <enabled>true</enabled>
-      </snapshots>
-      <id>spring-snapshots</id>
-      <name>Spring Snapshots</name>
-      <url>https://repo.spring.io/snapshot</url>
-    </repository>
-    <repository>
-      <snapshots>
-        <enabled>false</enabled>
-      </snapshots>
-      <id>spring-milestones</id>
-      <name>Spring Milestones</name>
-      <url>https://repo.spring.io/milestone</url>
-    </repository>
-  </repositories>
-  <pluginRepositories>
-    <pluginRepository>
-      <snapshots>
-        <enabled>true</enabled>
-      </snapshots>
-      <id>spring-snapshots</id>
-      <name>Spring Snapshots</name>
-      <url>https://repo.spring.io/snapshot</url>
-    </pluginRepository>
-    <pluginRepository>
-      <snapshots>
-        <enabled>false</enabled>
-      </snapshots>
-      <id>spring-milestones</id>
-      <name>Spring Milestones</name>
-      <url>https://repo.spring.io/milestone</url>
-    </pluginRepository>
-  </pluginRepositories>
-
   <profiles>
     <profile>
       <id>css</id>
diff --git a/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java b/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java
index 1382f3aea..13cb74301 100644
--- a/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java
+++ b/src/main/java/org/springframework/samples/petclinic/system/CacheConfiguration.java
@@ -16,7 +16,7 @@
 
 package org.springframework.samples.petclinic.system;
 
-import org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer;
+import org.springframework.boot.cache.autoconfigure.JCacheManagerCustomizer;
 import org.springframework.cache.annotation.EnableCaching;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
diff --git a/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
index a78e2e6e1..92fbf1d6d 100644
--- a/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/MySqlIntegrationTests.java
@@ -21,11 +21,11 @@ import static org.assertj.core.api.Assertions.assertThat;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.DisabledInNativeImage;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
-import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.boot.testcontainers.service.connection.ServiceConnection;
-import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.boot.web.server.test.LocalServerPort;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.RequestEntity;
 import org.springframework.http.ResponseEntity;
diff --git a/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
index 617af9652..002822ee6 100644
--- a/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/PetClinicIntegrationTests.java
@@ -21,10 +21,10 @@ import static org.assertj.core.api.Assertions.assertThat;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.SpringApplication;
+import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
-import org.springframework.boot.test.web.server.LocalServerPort;
-import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.boot.web.server.test.LocalServerPort;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.RequestEntity;
 import org.springframework.http.ResponseEntity;
diff --git a/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
index 709d33e66..a9b51c07b 100644
--- a/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/PostgresIntegrationTests.java
@@ -32,10 +32,10 @@ import org.junit.jupiter.api.condition.DisabledInNativeImage;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
+import org.springframework.boot.restclient.RestTemplateBuilder;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
-import org.springframework.boot.test.web.server.LocalServerPort;
-import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.boot.web.server.test.LocalServerPort;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.EnumerablePropertySource;
diff --git a/src/test/java/org/springframework/samples/petclinic/system/CrashControllerIntegrationTests.java b/src/test/java/org/springframework/samples/petclinic/system/CrashControllerIntegrationTests.java
index ed8b0819a..2d1ac0dd0 100644
--- a/src/test/java/org/springframework/samples/petclinic/system/CrashControllerIntegrationTests.java
+++ b/src/test/java/org/springframework/samples/petclinic/system/CrashControllerIntegrationTests.java
@@ -26,11 +26,11 @@ import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
-import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
-import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
+import org.springframework.boot.hibernate.autoconfigure.HibernateJpaAutoConfiguration;
+import org.springframework.boot.jdbc.autoconfigure.DataSourceAutoConfiguration;
+import org.springframework.boot.jdbc.autoconfigure.DataSourceTransactionManagerAutoConfiguration;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.web.server.test.client.TestRestTemplate;
 import org.springframework.core.ParameterizedTypeReference;
 import org.springframework.http.HttpEntity;
 import org.springframework.http.HttpHeaders;