diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 6672de2d6e7..c423ac8cb3c 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -31,7 +31,7 @@ retrofit = "2.9.0"
 slf4j = "1.7.30"
 springboot2 = "2.7.18"
 springboot3 = "3.5.0"
-springboot4 = "4.0.0-M3"
+springboot4 = "4.0.0-RC1"
 # Android
 targetSdk = "34"
 compileSdk = "34"
@@ -165,6 +165,7 @@ springboot3-starter-security = { module = "org.springframework.boot:spring-boot-
 springboot3-starter-jdbc = { module = "org.springframework.boot:spring-boot-starter-jdbc", version.ref = "springboot3" }
 springboot3-starter-actuator = { module = "org.springframework.boot:spring-boot-starter-actuator", version.ref = "springboot3" }
 springboot4-otel = { module = "io.opentelemetry.instrumentation:opentelemetry-spring-boot-starter", version.ref = "otelInstrumentation" }
+springboot4-resttestclient = { module = "org.springframework.boot:spring-boot-resttestclient", version.ref = "springboot4" }
 springboot4-starter = { module = "org.springframework.boot:spring-boot-starter", version.ref = "springboot4" }
 springboot4-starter-graphql = { module = "org.springframework.boot:spring-boot-starter-graphql", version.ref = "springboot4" }
 springboot4-starter-quartz = { module = "org.springframework.boot:spring-boot-starter-quartz", version.ref = "springboot4" }
diff --git a/sentry-spring-7/build.gradle.kts b/sentry-spring-7/build.gradle.kts
index a8071860ad0..8102909afb0 100644
--- a/sentry-spring-7/build.gradle.kts
+++ b/sentry-spring-7/build.gradle.kts
@@ -75,6 +75,7 @@ dependencies {
   testImplementation(libs.springboot4.starter.webflux)
   testImplementation(libs.springboot4.starter.restclient)
   testImplementation(libs.springboot4.starter.webclient)
+  testImplementation(libs.springboot4.resttestclient)
   testImplementation(projects.sentryReactor)
 }
 
diff --git a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/graphql/SentrySpringSubscriptionHandlerTest.kt b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/graphql/SentrySpringSubscriptionHandlerTest.kt
index c216b4595d2..1ed217037a2 100644
--- a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/graphql/SentrySpringSubscriptionHandlerTest.kt
+++ b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/graphql/SentrySpringSubscriptionHandlerTest.kt
@@ -40,8 +40,8 @@ class SentrySpringSubscriptionHandlerTest {
     whenever(parameters.environment).thenReturn(dataFetchingEnvironment)
     val resultObject =
       SentrySpringSubscriptionHandler()
-        .onSubscriptionResult(Flux.error<Any?>(exception), scopes, exceptionReporter, parameters)
-    assertThrows<IllegalStateException> { (resultObject as Flux<Any?>).blockFirst() }
+        .onSubscriptionResult(Flux.error<Any>(exception), scopes, exceptionReporter, parameters)
+    assertThrows<IllegalStateException> { (resultObject as Flux<Any>).blockFirst() }
 
     verify(exceptionReporter)
       .captureThrowable(
@@ -77,12 +77,12 @@ class SentrySpringSubscriptionHandlerTest {
     val resultObject =
       SentrySpringSubscriptionHandler()
         .onSubscriptionResult(
-          Flux.error<Any?>(wrappedException),
+          Flux.error<Any>(wrappedException),
           scopes,
           exceptionReporter,
           parameters,
         )
-    assertThrows<SubscriptionPublisherException> { (resultObject as Flux<Any?>).blockFirst() }
+    assertThrows<SubscriptionPublisherException> { (resultObject as Flux<Any>).blockFirst() }
 
     verify(exceptionReporter)
       .captureThrowable(
diff --git a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/mvc/SentrySpringIntegrationTest.kt b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/mvc/SentrySpringIntegrationTest.kt
index 1127456cc6c..169ef346865 100644
--- a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/mvc/SentrySpringIntegrationTest.kt
+++ b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/mvc/SentrySpringIntegrationTest.kt
@@ -22,7 +22,6 @@ import io.sentry.spring7.tracing.SentryTracingConfiguration
 import io.sentry.spring7.tracing.SentryTracingFilter
 import io.sentry.spring7.tracing.SentryTransaction
 import io.sentry.transport.ITransport
-import java.time.Duration
 import java.util.concurrent.Callable
 import java.util.concurrent.TimeUnit
 import kotlin.test.BeforeTest
@@ -42,9 +41,9 @@ import org.mockito.kotlin.verify
 import org.mockito.kotlin.whenever
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.resttestclient.TestRestTemplate
 import org.springframework.boot.test.context.SpringBootTest
-import org.springframework.boot.web.server.test.LocalServerPort
-import org.springframework.boot.web.server.test.client.TestRestTemplate
+import org.springframework.boot.test.web.server.LocalServerPort
 import org.springframework.boot.web.servlet.FilterRegistrationBean
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
@@ -80,13 +79,15 @@ import org.springframework.web.reactive.function.client.WebClient
 class SentrySpringIntegrationTest {
 
   companion object {
+    @JvmStatic
     @BeforeClass
-    fun `configure awaitlity`() {
+    fun `configure awaitlity`(): Unit {
       Awaitility.setDefaultTimeout(500, TimeUnit.MILLISECONDS)
     }
 
+    @JvmStatic
     @AfterClass
-    fun `reset awaitility`() {
+    fun `reset awaitility`(): Unit {
       Awaitility.reset()
     }
   }
@@ -230,10 +231,8 @@ class SentrySpringIntegrationTest {
 
     restTemplate.getForEntity("http://localhost:$port/throws-handled", String::class.java)
 
-    await.during(Duration.ofSeconds(2)).untilAsserted {
-      verify(transport, never())
-        .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
-    }
+    verify(transport, never())
+      .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
   }
 
   @Test
diff --git a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/webflux/SentryWebfluxIntegrationTest.kt b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/webflux/SentryWebfluxIntegrationTest.kt
index 2d44b40c27d..a91023b4ba0 100644
--- a/sentry-spring-7/src/test/kotlin/io/sentry/spring7/webflux/SentryWebfluxIntegrationTest.kt
+++ b/sentry-spring-7/src/test/kotlin/io/sentry/spring7/webflux/SentryWebfluxIntegrationTest.kt
@@ -27,10 +27,10 @@ import org.mockito.kotlin.whenever
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.ApplicationRunner
 import org.springframework.boot.autoconfigure.SpringBootApplication
-import org.springframework.boot.security.autoconfigure.reactive.ReactiveSecurityAutoConfiguration
-import org.springframework.boot.security.autoconfigure.servlet.SecurityAutoConfiguration
+import org.springframework.boot.security.autoconfigure.SecurityAutoConfiguration
+import org.springframework.boot.security.autoconfigure.web.reactive.ReactiveWebSecurityAutoConfiguration
 import org.springframework.boot.test.context.SpringBootTest
-import org.springframework.boot.web.server.test.LocalServerPort
+import org.springframework.boot.test.web.server.LocalServerPort
 import org.springframework.context.annotation.Bean
 import org.springframework.http.ResponseEntity
 import org.springframework.test.context.junit4.SpringRunner
@@ -136,7 +136,7 @@ class SentryWebfluxIntegrationTest {
 }
 
 @SpringBootApplication(
-  exclude = [ReactiveSecurityAutoConfiguration::class, SecurityAutoConfiguration::class]
+  exclude = [ReactiveWebSecurityAutoConfiguration::class, SecurityAutoConfiguration::class]
 )
 open class App {
   private val transport = mock<ITransport>().also { whenever(it.isHealthy).thenReturn(true) }
diff --git a/sentry-spring-boot-4/build.gradle.kts b/sentry-spring-boot-4/build.gradle.kts
index 897d59c3c20..96f2f39adab 100644
--- a/sentry-spring-boot-4/build.gradle.kts
+++ b/sentry-spring-boot-4/build.gradle.kts
@@ -102,6 +102,7 @@ dependencies {
   testImplementation(libs.springboot4.starter.webflux)
   testImplementation(libs.springboot4.starter.restclient)
   testImplementation(libs.springboot4.starter.webclient)
+  testImplementation(libs.springboot4.resttestclient)
 }
 
 configure<SourceSetContainer> { test { java.srcDir("src/test/java") } }
diff --git a/sentry-spring-boot-4/src/test/kotlin/io/sentry/spring/boot4/it/SentrySpringIntegrationTest.kt b/sentry-spring-boot-4/src/test/kotlin/io/sentry/spring/boot4/it/SentrySpringIntegrationTest.kt
index 998dfaaf867..473b60def12 100644
--- a/sentry-spring-boot-4/src/test/kotlin/io/sentry/spring/boot4/it/SentrySpringIntegrationTest.kt
+++ b/sentry-spring-boot-4/src/test/kotlin/io/sentry/spring/boot4/it/SentrySpringIntegrationTest.kt
@@ -24,9 +24,9 @@ import org.mockito.kotlin.whenever
 import org.slf4j.LoggerFactory
 import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.resttestclient.TestRestTemplate
 import org.springframework.boot.test.context.SpringBootTest
-import org.springframework.boot.web.server.test.LocalServerPort
-import org.springframework.boot.web.server.test.client.TestRestTemplate
+import org.springframework.boot.test.web.server.LocalServerPort
 import org.springframework.context.annotation.Bean
 import org.springframework.context.annotation.Configuration
 import org.springframework.http.HttpEntity
diff --git a/sentry-spring-jakarta/src/test/kotlin/io/sentry/spring/jakarta/mvc/SentrySpringIntegrationTest.kt b/sentry-spring-jakarta/src/test/kotlin/io/sentry/spring/jakarta/mvc/SentrySpringIntegrationTest.kt
index 6e2ea53fdfd..9630460cd98 100644
--- a/sentry-spring-jakarta/src/test/kotlin/io/sentry/spring/jakarta/mvc/SentrySpringIntegrationTest.kt
+++ b/sentry-spring-jakarta/src/test/kotlin/io/sentry/spring/jakarta/mvc/SentrySpringIntegrationTest.kt
@@ -22,7 +22,6 @@ import io.sentry.spring.jakarta.tracing.SentryTracingConfiguration
 import io.sentry.spring.jakarta.tracing.SentryTracingFilter
 import io.sentry.spring.jakarta.tracing.SentryTransaction
 import io.sentry.transport.ITransport
-import java.time.Duration
 import java.util.concurrent.Callable
 import java.util.concurrent.TimeUnit
 import kotlin.test.BeforeTest
@@ -230,10 +229,8 @@ class SentrySpringIntegrationTest {
 
     restTemplate.getForEntity("http://localhost:$port/throws-handled", String::class.java)
 
-    await.during(Duration.ofSeconds(2)).untilAsserted {
-      verify(transport, never())
-        .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
-    }
+    verify(transport, never())
+      .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
   }
 
   @Test
diff --git a/sentry-spring/src/test/kotlin/io/sentry/spring/mvc/SentrySpringIntegrationTest.kt b/sentry-spring/src/test/kotlin/io/sentry/spring/mvc/SentrySpringIntegrationTest.kt
index d6c5fd2aa79..63d29dd78db 100644
--- a/sentry-spring/src/test/kotlin/io/sentry/spring/mvc/SentrySpringIntegrationTest.kt
+++ b/sentry-spring/src/test/kotlin/io/sentry/spring/mvc/SentrySpringIntegrationTest.kt
@@ -22,7 +22,6 @@ import io.sentry.spring.tracing.SentryTracingConfiguration
 import io.sentry.spring.tracing.SentryTracingFilter
 import io.sentry.spring.tracing.SentryTransaction
 import io.sentry.transport.ITransport
-import java.time.Duration
 import java.util.concurrent.Callable
 import java.util.concurrent.TimeUnit
 import kotlin.test.BeforeTest
@@ -231,10 +230,8 @@ class SentrySpringIntegrationTest {
 
     restTemplate.getForEntity("http://localhost:$port/throws-handled", String::class.java)
 
-    await.during(Duration.ofSeconds(2)).untilAsserted {
-      verify(transport, never())
-        .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
-    }
+    verify(transport, never())
+      .send(checkEvent { event -> assertThat(event).isNotNull() }, anyOrNull())
   }
 
   @Test