diff --git a/integration-tests/pom.xml b/integration-tests/pom.xml
index 1a3a8c41..6e60ef81 100644
--- a/integration-tests/pom.xml
+++ b/integration-tests/pom.xml
@@ -35,10 +35,15 @@
       <artifactId>spring-boot-starter-test</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-webmvc-test</artifactId>
+      <scope>test</scope>
+    </dependency>
 
     <dependency>
-      <groupId>org.springframework.security</groupId>
-      <artifactId>spring-security-test</artifactId>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-security-test</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>
diff --git a/integration-tests/src/test/java/my/bookshop/it/FeatureTogglesIT.java b/integration-tests/src/test/java/my/bookshop/it/FeatureTogglesIT.java
index e266e334..936c9802 100644
--- a/integration-tests/src/test/java/my/bookshop/it/FeatureTogglesIT.java
+++ b/integration-tests/src/test/java/my/bookshop/it/FeatureTogglesIT.java
@@ -7,8 +7,8 @@
 
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
 import org.springframework.security.test.context.support.WithMockUser;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.servlet.MockMvc;
diff --git a/pom.xml b/pom.xml
index 7456aae1..7890b18d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -5,7 +5,7 @@
   <parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
-    <version>3.5.14</version>
+    <version>4.1.0</version>
     <relativePath/>
     <!-- lookup parent from repository -->
   </parent>
@@ -28,9 +28,9 @@
 
     <!-- DEPENDENCIES VERSION -->
     <jdk.version>25</jdk.version>
-    <cds.services.version>4.9.0</cds.services.version>
+    <cds.services.version>5.0.0-m2624</cds.services.version>
     <cloud.sdk.version>5.30.0</cloud.sdk.version>
-    <xsuaa.version>3.7.3</xsuaa.version>
+    <xsuaa.version>4.0.0</xsuaa.version>
     <cf-java-logging-support.version>4.2.0</cf-java-logging-support.version>
     <cds-feature-attachments.version>1.5.0</cds-feature-attachments.version>
   </properties>
diff --git a/srv/pom.xml b/srv/pom.xml
index eca15c24..b05e2411 100644
--- a/srv/pom.xml
+++ b/srv/pom.xml
@@ -110,6 +110,11 @@
       <artifactId>spring-boot-starter-security</artifactId>
     </dependency>
 
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-security-oauth2-resource-server</artifactId>
+    </dependency>
+
     <dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-actuator</artifactId>
@@ -122,14 +127,26 @@
     </dependency>
 
     <dependency>
-      <groupId>org.springframework.security</groupId>
-      <artifactId>spring-security-test</artifactId>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-security-test</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-webclient</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-webtestclient</artifactId>
       <scope>test</scope>
     </dependency>
 
     <dependency>
       <groupId>org.springframework.boot</groupId>
-      <artifactId>spring-boot-starter-webflux</artifactId>
+      <artifactId>spring-boot-starter-webmvc-test</artifactId>
       <scope>test</scope>
     </dependency>
 
diff --git a/srv/src/main/java/my/bookshop/health/CustomHealthIndicator.java b/srv/src/main/java/my/bookshop/health/CustomHealthIndicator.java
index 4ecd1295..c8abcec6 100644
--- a/srv/src/main/java/my/bookshop/health/CustomHealthIndicator.java
+++ b/srv/src/main/java/my/bookshop/health/CustomHealthIndicator.java
@@ -1,8 +1,8 @@
 package my.bookshop.health;
 
-import org.springframework.boot.actuate.autoconfigure.health.ConditionalOnEnabledHealthIndicator;
-import org.springframework.boot.actuate.health.Health;
-import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.health.autoconfigure.contributor.ConditionalOnEnabledHealthIndicator;
+import org.springframework.boot.health.contributor.Health;
+import org.springframework.boot.health.contributor.HealthIndicator;
 import org.springframework.stereotype.Component;
 
 /** Custom health indicator implementation. */
diff --git a/srv/src/test/java/my/bookshop/AdminServiceAddress_default_ITest.java b/srv/src/test/java/my/bookshop/AdminServiceAddress_default_ITest.java
index 63eef15f..90f4a4b9 100644
--- a/srv/src/test/java/my/bookshop/AdminServiceAddress_default_ITest.java
+++ b/srv/src/test/java/my/bookshop/AdminServiceAddress_default_ITest.java
@@ -3,6 +3,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.webtestclient.autoconfigure.AutoConfigureWebTestClient;
 import org.springframework.test.context.ActiveProfiles;
 
 /**
@@ -12,6 +13,7 @@
  */
 @ActiveProfiles("default")
 @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+@AutoConfigureWebTestClient
 class AdminServiceAddress_default_ITest extends AdminServiceAddressITestBase {
 
   @Test
diff --git a/srv/src/test/java/my/bookshop/AdminServiceAddress_mocked_ITest.java b/srv/src/test/java/my/bookshop/AdminServiceAddress_mocked_ITest.java
index bd43bb1b..c2f63def 100644
--- a/srv/src/test/java/my/bookshop/AdminServiceAddress_mocked_ITest.java
+++ b/srv/src/test/java/my/bookshop/AdminServiceAddress_mocked_ITest.java
@@ -3,6 +3,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.webtestclient.autoconfigure.AutoConfigureWebTestClient;
 import org.springframework.test.context.ActiveProfiles;
 
 /**
@@ -16,6 +17,7 @@
     webEnvironment = WebEnvironment.RANDOM_PORT,
     properties =
         "cds.remote.services.'[API_BUSINESS_PARTNER]'.destination.name=myself-AdminServiceAddressITest")
+@AutoConfigureWebTestClient
 class AdminServiceAddress_mocked_ITest extends AdminServiceAddressITestBase {
 
   @Test
diff --git a/srv/src/test/java/my/bookshop/CatalogServiceITest.java b/srv/src/test/java/my/bookshop/CatalogServiceITest.java
index ee71ea3e..0902d7ee 100644
--- a/srv/src/test/java/my/bookshop/CatalogServiceITest.java
+++ b/srv/src/test/java/my/bookshop/CatalogServiceITest.java
@@ -1,12 +1,7 @@
 package my.bookshop;
 
 import static cds.gen.catalogservice.CatalogService_.REVIEWS;
-import static org.hamcrest.CoreMatchers.containsString;
-import static org.hamcrest.CoreMatchers.not;
-import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
-import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
-import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
-import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import cds.gen.catalogservice.Reviews;
 import com.sap.cds.ql.Delete;
@@ -14,14 +9,14 @@
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.resttestclient.autoconfigure.AutoConfigureRestTestClient;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.http.MediaType;
 import org.springframework.security.test.context.support.WithMockUser;
-import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.client.RestTestClient;
 
 @SpringBootTest
-@AutoConfigureMockMvc
+@AutoConfigureRestTestClient
 class CatalogServiceITest {
 
   private static final String booksURI = "/api/browse/Books";
@@ -32,7 +27,7 @@ class CatalogServiceITest {
   private static final String USER_USER_STRING = "user";
   private static final String ADMIN_USER_STRING = "admin";
 
-  @Autowired private MockMvc mockMvc;
+  @Autowired private RestTestClient client;
 
   @Autowired private PersistenceService db;
 
@@ -42,47 +37,76 @@ void cleanup() {
   }
 
   @Test
-  void discountApplied() throws Exception {
-    mockMvc
-        .perform(get(booksURI + "?$filter=stock gt 200&top=1"))
-        .andExpect(status().isOk())
-        .andExpect(jsonPath("$.value[0].title").value(containsString("11% discount")));
+  void discountApplied() {
+    client
+        .get()
+        .uri(booksURI + "?$filter=stock gt 200&top=1")
+        .exchange()
+        .expectStatus()
+        .isOk()
+        .expectBody()
+        .jsonPath("$.value[0].title")
+        .value(String.class, title -> assertThat(title).contains("11% discount"));
   }
 
   @Test
-  void discountNotApplied() throws Exception {
-    mockMvc
-        .perform(get(booksURI + "?$filter=stock lt 100&top=1"))
-        .andExpect(status().isOk())
-        .andExpect(jsonPath("$.value[0].title").value(not(containsString("11% discount"))));
+  void discountNotApplied() {
+    client
+        .get()
+        .uri(booksURI + "?$filter=stock lt 100&top=1")
+        .exchange()
+        .expectStatus()
+        .isOk()
+        .expectBody()
+        .jsonPath("$.value[0].title")
+        .value(String.class, title -> assertThat(title).doesNotContain("11% discount"));
   }
 
   @Test
-  void createReviewNotAuthenticated() throws Exception {
+  void createReviewNotAuthenticated() {
     String payload = createTestReview().toJson();
-    mockMvc
-        .perform(post(addReviewURI).contentType(MediaType.APPLICATION_JSON).content(payload))
-        .andExpect(status().isUnauthorized());
+    client
+        .post()
+        .uri(addReviewURI)
+        .contentType(MediaType.APPLICATION_JSON)
+        .body(payload)
+        .exchange()
+        .expectStatus()
+        .isUnauthorized();
   }
 
   @Test
   @WithMockUser(USER_USER_STRING)
-  void createReviewByUser() throws Exception {
+  void createReviewByUser() {
     String payload = createTestReview().toJson();
-    mockMvc
-        .perform(post(addReviewURI).contentType(MediaType.APPLICATION_JSON).content(payload))
-        .andExpect(status().isOk())
-        .andExpect(jsonPath("$.createdBy").value(USER_USER_STRING));
+    client
+        .post()
+        .uri(addReviewURI)
+        .contentType(MediaType.APPLICATION_JSON)
+        .body(payload)
+        .exchange()
+        .expectStatus()
+        .isOk()
+        .expectBody()
+        .jsonPath("$.createdBy")
+        .isEqualTo(USER_USER_STRING);
   }
 
   @Test
   @WithMockUser(ADMIN_USER_STRING)
-  void createReviewByAdmin() throws Exception {
+  void createReviewByAdmin() {
     String payload = createTestReview().toJson();
-    mockMvc
-        .perform(post(addReviewURI).contentType(MediaType.APPLICATION_JSON).content(payload))
-        .andExpect(status().isOk())
-        .andExpect(jsonPath("$.createdBy").value(ADMIN_USER_STRING));
+    client
+        .post()
+        .uri(addReviewURI)
+        .contentType(MediaType.APPLICATION_JSON)
+        .body(payload)
+        .exchange()
+        .expectStatus()
+        .isOk()
+        .expectBody()
+        .jsonPath("$.createdBy")
+        .isEqualTo(ADMIN_USER_STRING);
   }
 
   private Reviews createTestReview() {
diff --git a/srv/src/test/java/my/bookshop/GenreHierarchyTest.java b/srv/src/test/java/my/bookshop/GenreHierarchyTest.java
index d01f82ea..cb855973 100644
--- a/srv/src/test/java/my/bookshop/GenreHierarchyTest.java
+++ b/srv/src/test/java/my/bookshop/GenreHierarchyTest.java
@@ -7,8 +7,8 @@
 import java.net.URI;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
 import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.webmvc.test.autoconfigure.AutoConfigureMockMvc;
 import org.springframework.security.test.context.support.WithMockUser;
 import org.springframework.test.web.servlet.MockMvc;
 import org.springframework.web.util.UriComponentsBuilder;
diff --git a/srv/src/test/java/my/bookshop/NotesServiceITest.java b/srv/src/test/java/my/bookshop/NotesServiceITest.java
index cc6c68b2..b4179bf9 100644
--- a/srv/src/test/java/my/bookshop/NotesServiceITest.java
+++ b/srv/src/test/java/my/bookshop/NotesServiceITest.java
@@ -4,6 +4,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.webtestclient.autoconfigure.AutoConfigureWebTestClient;
 import org.springframework.http.HttpHeaders;
 import org.springframework.test.context.ActiveProfiles;
 import org.springframework.test.web.reactive.server.WebTestClient;
@@ -12,6 +13,7 @@
     webEnvironment = WebEnvironment.RANDOM_PORT,
     properties =
         "cds.remote.services.'[API_BUSINESS_PARTNER]'.destination.name=myself-NotesServiceITest")
+@AutoConfigureWebTestClient
 @ActiveProfiles({"default", "mocked"})
 class NotesServiceITest {