diff --git a/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferDecoder.java b/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferDecoder.java
index 384d4821d3c..f8e4aa4c0cf 100644
--- a/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferDecoder.java
+++ b/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferDecoder.java
@@ -34,7 +34,10 @@ import org.springframework.util.MimeTypeUtils;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class Netty5BufferDecoder extends AbstractDataBufferDecoder<Buffer> {
 
 	public Netty5BufferDecoder() {
diff --git a/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferEncoder.java b/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferEncoder.java
index 9e0b1df4b6e..fbb787dcff5 100644
--- a/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferEncoder.java
+++ b/spring-core/src/main/java/org/springframework/core/codec/Netty5BufferEncoder.java
@@ -35,7 +35,10 @@ import org.springframework.util.MimeTypeUtils;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class Netty5BufferEncoder extends AbstractEncoder<Buffer> {
 
 	public Netty5BufferEncoder() {
diff --git a/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBuffer.java b/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBuffer.java
index aedeea7d20f..0e9afcad0e2 100644
--- a/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBuffer.java
+++ b/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBuffer.java
@@ -36,7 +36,10 @@ import org.springframework.util.ObjectUtils;
  * @author Violeta Georgieva
  * @author Arjen Poutsma
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public final class Netty5DataBuffer implements CloseableDataBuffer, TouchableDataBuffer {
 
 	private final Buffer buffer;
diff --git a/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBufferFactory.java b/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBufferFactory.java
index aec57a5108b..279b373519f 100644
--- a/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBufferFactory.java
+++ b/spring-core/src/main/java/org/springframework/core/io/buffer/Netty5DataBufferFactory.java
@@ -33,7 +33,10 @@ import org.springframework.util.Assert;
  * @author Violeta Georgieva
  * @author Arjen Poutsma
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class Netty5DataBufferFactory implements DataBufferFactory {
 
 	private final BufferAllocator bufferAllocator;
diff --git a/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferDecoderTests.java b/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferDecoderTests.java
index d346d2b3893..9d4f12bf3f7 100644
--- a/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferDecoderTests.java
+++ b/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferDecoderTests.java
@@ -34,6 +34,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 /**
  * @author Arjen Poutsma
  */
+@SuppressWarnings("removal")
 class Netty5BufferDecoderTests extends AbstractDecoderTests<Netty5BufferDecoder> {
 
 	private final byte[] fooBytes = "foo".getBytes(StandardCharsets.UTF_8);
diff --git a/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferEncoderTests.java b/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferEncoderTests.java
index af57fd3098a..f11cdec8e61 100644
--- a/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferEncoderTests.java
+++ b/spring-core/src/test/java/org/springframework/core/codec/Netty5BufferEncoderTests.java
@@ -32,6 +32,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 /**
  * @author Arjen Poutsma
  */
+@SuppressWarnings("removal")
 class Netty5BufferEncoderTests extends AbstractEncoderTests<Netty5BufferEncoder> {
 
 	private final byte[] fooBytes = "foo".getBytes(StandardCharsets.UTF_8);
diff --git a/spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java b/spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java
index 30690dfa085..294df737939 100644
--- a/spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java
+++ b/spring-core/src/test/java/org/springframework/core/io/buffer/DataBufferTests.java
@@ -457,7 +457,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void decreaseCapacityLowReadPosition(DataBufferFactory bufferFactory) {
 		assumeThat(bufferFactory).as("Netty 5 does not support decreasing the capacity")
 				.isNotInstanceOf(Netty5DataBufferFactory.class);
@@ -473,7 +473,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void decreaseCapacityHighReadPosition(DataBufferFactory bufferFactory) {
 		assumeThat(bufferFactory).as("Netty 5 does not support decreasing the capacity")
 				.isNotInstanceOf(Netty5DataBufferFactory.class);
@@ -578,6 +578,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
+	@SuppressWarnings("removal")
 	void asByteBufferIndexLength(DataBufferFactory bufferFactory) {
 		super.bufferFactory = bufferFactory;
 
@@ -604,7 +605,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void byteBufferContainsDataBufferChanges(DataBufferFactory bufferFactory) {
 		assumeThat(bufferFactory).as("Netty 5 does not support sharing data between buffers")
 				.isNotInstanceOf(Netty5DataBufferFactory.class);
@@ -624,7 +625,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void dataBufferContainsByteBufferChanges(DataBufferFactory bufferFactory) {
 		assumeThat(bufferFactory).as("Netty 5 does not support sharing data between buffers")
 				.isNotInstanceOf(Netty5DataBufferFactory.class);
@@ -857,7 +858,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void slice(DataBufferFactory bufferFactory) {
 		super.bufferFactory = bufferFactory;
 
@@ -885,7 +886,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void retainedSlice(DataBufferFactory bufferFactory) {
 		assumeThat(bufferFactory).as("Netty 5 does not support retainedSlice")
 				.isNotInstanceOf(Netty5DataBufferFactory.class);
@@ -915,7 +916,7 @@ class DataBufferTests extends AbstractDataBufferAllocatingTests {
 	}
 
 	@ParameterizedDataBufferAllocatingTest
-	@SuppressWarnings("deprecation")
+	@SuppressWarnings({"deprecation", "removal"})
 	void spr16351(DataBufferFactory bufferFactory) {
 		super.bufferFactory = bufferFactory;
 
diff --git a/spring-core/src/test/java/org/springframework/util/concurrent/MonoToListenableFutureAdapterTests.java b/spring-core/src/test/java/org/springframework/util/concurrent/MonoToListenableFutureAdapterTests.java
index 33d83ec4326..8b3d22ea1ac 100644
--- a/spring-core/src/test/java/org/springframework/util/concurrent/MonoToListenableFutureAdapterTests.java
+++ b/spring-core/src/test/java/org/springframework/util/concurrent/MonoToListenableFutureAdapterTests.java
@@ -44,7 +44,6 @@ class MonoToListenableFutureAdapterTests {
 	}
 
 	@Test
-	@SuppressWarnings("deprecation")
 	void failure() {
 		Throwable expected = new IllegalStateException("oops");
 		AtomicReference<Object> actual = new AtomicReference<>();
diff --git a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/AbstractDataBufferAllocatingTests.java b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/AbstractDataBufferAllocatingTests.java
index 3da840f69e2..80c6c6a2053 100644
--- a/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/AbstractDataBufferAllocatingTests.java
+++ b/spring-core/src/testFixtures/java/org/springframework/core/testfixture/io/buffer/AbstractDataBufferAllocatingTests.java
@@ -201,6 +201,7 @@ public abstract class AbstractDataBufferAllocatingTests {
 	public @interface ParameterizedDataBufferAllocatingTest {
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Arguments> dataBufferFactories() {
 		return Stream.of(
 			// Netty 4
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClient.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClient.java
index 43d8cbc9176..893558d675f 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClient.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClient.java
@@ -74,6 +74,7 @@ public class ReactorNettyTcpStompClient extends StompClientSupport {
 		this.tcpClient = tcpClient;
 	}
 
+	@SuppressWarnings("removal")
 	private static TcpOperations<byte[]> initTcpClient(String host, int port) {
 		if (reactorNettyClientPresent) {
 			ReactorNettyTcpClient<byte[]> client = new ReactorNettyTcpClient<>(host, port, new StompReactorNettyCodec());
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java
index b63574e126d..88388d86269 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/StompBrokerRelayMessageHandler.java
@@ -356,8 +356,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 
 	/**
 	 * Configure a TCP client for managing TCP connections to the STOMP broker.
-	 * <p>By default {@link ReactorNettyTcpClient} or
-	 * {@link ReactorNetty2TcpClient} is used.
+	 * <p>By default {@link ReactorNettyTcpClient} is used.
 	 * <p><strong>Note:</strong> when this property is used, any
 	 * {@link #setRelayHost(String) host} or {@link #setRelayPort(int) port}
 	 * specified are effectively ignored.
@@ -470,6 +469,7 @@ public class StompBrokerRelayMessageHandler extends AbstractBrokerMessageHandler
 		}
 	}
 
+	@SuppressWarnings("removal")
 	private TcpOperations<byte[]> initTcpClient() {
 		StompDecoder decoder = new StompDecoder();
 		if (this.headerInitializer != null) {
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpClient.java b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpClient.java
index dfd87c0d38f..3c5fa709586 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpClient.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpClient.java
@@ -60,7 +60,10 @@ import org.springframework.util.Assert;
  * @author Rossen Stoyanchev
  * @since 6.0
  * @param <P> the type of payload for in and outbound messages
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class ReactorNetty2TcpClient<P> implements TcpOperations<P> {
 
 	private static final int PUBLISH_ON_BUFFER_SIZE = 16;
diff --git a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpConnection.java b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpConnection.java
index 30e23cd0cfc..e3abdd41a9c 100644
--- a/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpConnection.java
+++ b/spring-messaging/src/main/java/org/springframework/messaging/tcp/reactor/ReactorNetty2TcpConnection.java
@@ -36,7 +36,9 @@ import org.springframework.messaging.tcp.TcpConnection;
  * @author Rossen Stoyanchev
  * @since 6.0
  * @param <P> the type of payload for outbound messages
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class ReactorNetty2TcpConnection<P> implements TcpConnection<P> {
 
 	private final NettyInbound inbound;
diff --git a/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNetty2StompBrokerRelayIntegrationTests.java b/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNetty2StompBrokerRelayIntegrationTests.java
index c3ef8e0fc68..85dc48117e1 100644
--- a/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNetty2StompBrokerRelayIntegrationTests.java
+++ b/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNetty2StompBrokerRelayIntegrationTests.java
@@ -28,6 +28,7 @@ import org.springframework.messaging.tcp.reactor.ReactorNetty2TcpClient;
  * @author Rossen Stoyanchev
  */
 @Disabled("gh-29287 :: Disabled because they fail too frequently")
+@SuppressWarnings("removal")
 public class ReactorNetty2StompBrokerRelayIntegrationTests extends AbstractStompBrokerRelayIntegrationTests {
 
 	@Override
diff --git a/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClientTests.java b/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClientTests.java
index e9d8e2d9665..cdc31017c47 100644
--- a/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClientTests.java
+++ b/spring-messaging/src/test/java/org/springframework/messaging/simp/stomp/ReactorNettyTcpStompClientTests.java
@@ -62,6 +62,7 @@ class ReactorNettyTcpStompClientTests {
 
 
 	@BeforeEach
+	@SuppressWarnings("removal")
 	void setup(TestInfo testInfo) throws Exception {
 		logger.debug("Setting up before '" + testInfo.getTestMethod().get().getName() + "'");
 
diff --git a/spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClientBuilder.java b/spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClientBuilder.java
index 6114a8bb0c9..8034500359b 100644
--- a/spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClientBuilder.java
+++ b/spring-test/src/main/java/org/springframework/test/web/reactive/server/DefaultWebTestClientBuilder.java
@@ -314,6 +314,7 @@ class DefaultWebTestClientBuilder implements WebTestClient.Builder {
 				this.entityResultConsumer, this.responseTimeout, new DefaultWebTestClientBuilder(this));
 	}
 
+	@SuppressWarnings("removal")
 	private static ClientHttpConnector initConnector() {
 		if (reactorNettyClientPresent) {
 			return new ReactorClientHttpConnector();
diff --git a/spring-web/src/jmh/java/org/springframework/http/support/HeadersAdapterBenchmark.java b/spring-web/src/jmh/java/org/springframework/http/support/HeadersAdapterBenchmark.java
index 20414058ac1..31317c178a0 100644
--- a/spring-web/src/jmh/java/org/springframework/http/support/HeadersAdapterBenchmark.java
+++ b/spring-web/src/jmh/java/org/springframework/http/support/HeadersAdapterBenchmark.java
@@ -77,6 +77,7 @@ public class HeadersAdapterBenchmark {
 		// Uncomment the following line and comment the similar line for setupImplementationBaseline below
 		// to benchmark current implementations
 		@Setup(Level.Trial)
+		@SuppressWarnings("removal")
 		public void initImplementationNew() {
 			this.entriesProvider = map -> new HttpHeaders(map).headerSet();
 
diff --git a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpConnector.java b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpConnector.java
index 9e7dadc4022..e87dad03408 100644
--- a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpConnector.java
+++ b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpConnector.java
@@ -40,7 +40,10 @@ import org.springframework.util.Assert;
  * @author Violeta Georgieva
  * @since 6.0
  * @see HttpClient
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class ReactorNetty2ClientHttpConnector implements ClientHttpConnector {
 
 	/**
diff --git a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpRequest.java b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpRequest.java
index 6d3b34582b8..84cfef74527 100644
--- a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpRequest.java
+++ b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpRequest.java
@@ -45,6 +45,7 @@ import org.springframework.http.support.Netty5HeadersAdapter;
  * @since 6.0
  * @see reactor.netty5.http.client.HttpClient
  */
+@SuppressWarnings("removal")
 class ReactorNetty2ClientHttpRequest extends AbstractClientHttpRequest implements ZeroCopyHttpOutputMessage {
 
 	private final HttpMethod httpMethod;
diff --git a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpResponse.java b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpResponse.java
index 9792c07a883..bc9efa99484 100644
--- a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpResponse.java
+++ b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ClientHttpResponse.java
@@ -52,6 +52,7 @@ import org.springframework.util.ObjectUtils;
  * @since 6.0
  * @see reactor.netty5.http.client.HttpClient
  */
+@SuppressWarnings("removal")
 class ReactorNetty2ClientHttpResponse implements ClientHttpResponse {
 
 	private static final Log logger = LogFactory.getLog(ReactorNetty2ClientHttpResponse.class);
diff --git a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ResourceFactory.java b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ResourceFactory.java
index cc5f03d86cb..5a046055578 100644
--- a/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ResourceFactory.java
+++ b/spring-web/src/main/java/org/springframework/http/client/reactive/ReactorNetty2ResourceFactory.java
@@ -42,7 +42,9 @@ import org.springframework.util.Assert;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class ReactorNetty2ResourceFactory implements InitializingBean, DisposableBean {
 
 	private boolean useGlobalResources = true;
diff --git a/spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java b/spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java
index 159ad407843..472dbd11429 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/support/BaseDefaultCodecs.java
@@ -33,8 +33,6 @@ import org.springframework.core.codec.DataBufferDecoder;
 import org.springframework.core.codec.DataBufferEncoder;
 import org.springframework.core.codec.Decoder;
 import org.springframework.core.codec.Encoder;
-import org.springframework.core.codec.Netty5BufferDecoder;
-import org.springframework.core.codec.Netty5BufferEncoder;
 import org.springframework.core.codec.NettyByteBufDecoder;
 import org.springframework.core.codec.NettyByteBufEncoder;
 import org.springframework.core.codec.ResourceDecoder;
@@ -417,6 +415,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 	 * Reset and initialize typed readers.
 	 * @since 5.3.3
 	 */
+	@SuppressWarnings("removal")
 	protected void initTypedReaders() {
 		this.typedReaders.clear();
 		if (!this.registerDefaults) {
@@ -429,7 +428,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 			addCodec(this.typedReaders, new DecoderHttpMessageReader<>(new NettyByteBufDecoder()));
 		}
 		if (netty5BufferPresent) {
-			addCodec(this.typedReaders, new DecoderHttpMessageReader<>(new Netty5BufferDecoder()));
+			addCodec(this.typedReaders, new DecoderHttpMessageReader<>(new org.springframework.core.codec.Netty5BufferDecoder()));
 		}
 		addCodec(this.typedReaders, new ResourceHttpMessageReader(new ResourceDecoder()));
 		addCodec(this.typedReaders, new DecoderHttpMessageReader<>(StringDecoder.textPlainOnly()));
@@ -667,6 +666,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 	/**
 	 * Return "base" typed writers only, i.e. common to client and server.
 	 */
+	@SuppressWarnings("removal")
 	final List<HttpMessageWriter<?>> getBaseTypedWriters() {
 		if (!this.registerDefaults) {
 			return Collections.emptyList();
@@ -679,7 +679,7 @@ class BaseDefaultCodecs implements CodecConfigurer.DefaultCodecs, CodecConfigure
 			addCodec(writers, new EncoderHttpMessageWriter<>(new NettyByteBufEncoder()));
 		}
 		if (netty5BufferPresent) {
-			addCodec(writers, new EncoderHttpMessageWriter<>(new Netty5BufferEncoder()));
+			addCodec(writers, new EncoderHttpMessageWriter<>(new org.springframework.core.codec.Netty5BufferEncoder()));
 		}
 		addCodec(writers, new ResourceHttpMessageWriter());
 		addCodec(writers, new EncoderHttpMessageWriter<>(CharSequenceEncoder.textPlainOnly()));
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2HttpHandlerAdapter.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2HttpHandlerAdapter.java
index 82185dfe910..a835ce18812 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2HttpHandlerAdapter.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2HttpHandlerAdapter.java
@@ -37,7 +37,10 @@ import org.springframework.util.Assert;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class ReactorNetty2HttpHandlerAdapter implements BiFunction<HttpServerRequest, HttpServerResponse, Mono<Void>> {
 
 	private static final Log logger = HttpLogging.forLogName(ReactorNetty2HttpHandlerAdapter.class);
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpRequest.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpRequest.java
index 363e0c460e3..769e355998a 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpRequest.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpRequest.java
@@ -53,6 +53,7 @@ import org.springframework.util.MultiValueMap;
  * @author Sebastien Deleuze
  * @since 6.0
  */
+@SuppressWarnings("removal")
 class ReactorNetty2ServerHttpRequest extends AbstractServerHttpRequest {
 
 	private static final Log logger = HttpLogging.forLogName(ReactorNetty2ServerHttpRequest.class);
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpResponse.java b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpResponse.java
index 17ba0ecae88..1fd7bba2260 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpResponse.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/ReactorNetty2ServerHttpResponse.java
@@ -49,6 +49,7 @@ import org.springframework.util.Assert;
  * @author Violeta Georgieva
  * @since 6.0
  */
+@SuppressWarnings("removal")
 class ReactorNetty2ServerHttpResponse extends AbstractServerHttpResponse implements ZeroCopyHttpOutputMessage {
 
 	private static final Log logger = LogFactory.getLog(ReactorNetty2ServerHttpResponse.class);
diff --git a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
index 8028ab37c40..24b0556434e 100644
--- a/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
+++ b/spring-web/src/main/java/org/springframework/http/server/reactive/UndertowHttpHandlerAdapter.java
@@ -37,7 +37,9 @@ import org.springframework.util.Assert;
  * @author Rossen Stoyanchev
  * @author Arjen Poutsma
  * @since 5.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class UndertowHttpHandlerAdapter implements io.undertow.server.HttpHandler {
 
 	private static final Log logger = HttpLogging.forLogName(UndertowHttpHandlerAdapter.class);
diff --git a/spring-web/src/main/java/org/springframework/http/support/Netty5HeadersAdapter.java b/spring-web/src/main/java/org/springframework/http/support/Netty5HeadersAdapter.java
index b3199ecdc6a..112d208923f 100644
--- a/spring-web/src/main/java/org/springframework/http/support/Netty5HeadersAdapter.java
+++ b/spring-web/src/main/java/org/springframework/http/support/Netty5HeadersAdapter.java
@@ -40,7 +40,10 @@ import org.springframework.util.MultiValueMap;
  * @author Violeta Georgieva
  * @author Simon Baslé
  * @since 6.1
+ * deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public final class Netty5HeadersAdapter implements MultiValueMap<String, String> {
 
 	private final HttpHeaders headers;
diff --git a/spring-web/src/main/java/org/springframework/web/util/ContentCachingRequestWrapper.java b/spring-web/src/main/java/org/springframework/web/util/ContentCachingRequestWrapper.java
index abfb70e4014..e747aebe91f 100644
--- a/spring-web/src/main/java/org/springframework/web/util/ContentCachingRequestWrapper.java
+++ b/spring-web/src/main/java/org/springframework/web/util/ContentCachingRequestWrapper.java
@@ -71,7 +71,10 @@ public class ContentCachingRequestWrapper extends HttpServletRequestWrapper {
 	/**
 	 * Create a new ContentCachingRequestWrapper for the given servlet request.
 	 * @param request the original servlet request
+	 * @deprecated in favor of {@link #ContentCachingRequestWrapper(HttpServletRequest, int)}
+	 * in order to explicitly choose the cache limit
 	 */
+	@Deprecated(since = "6.2.18", forRemoval = true)
 	public ContentCachingRequestWrapper(HttpServletRequest request) {
 		super(request);
 		int contentLength = request.getContentLength();
diff --git a/spring-web/src/test/java/org/springframework/http/codec/support/ClientCodecConfigurerTests.java b/spring-web/src/test/java/org/springframework/http/codec/support/ClientCodecConfigurerTests.java
index 0216be4a825..5038684eae9 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/support/ClientCodecConfigurerTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/support/ClientCodecConfigurerTests.java
@@ -94,6 +94,7 @@ class ClientCodecConfigurerTests {
 
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultReaders() {
 		List<HttpMessageReader<?>> readers = this.configurer.getReaders();
 		assertThat(readers).hasSize(20);
@@ -121,6 +122,7 @@ class ClientCodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultWriters() {
 		List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
 		assertThat(writers).hasSize(18);
@@ -188,6 +190,7 @@ class ClientCodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void maxInMemorySize() {
 		int size = 99;
 		this.configurer.defaultCodecs().maxInMemorySize(size);
diff --git a/spring-web/src/test/java/org/springframework/http/codec/support/CodecConfigurerTests.java b/spring-web/src/test/java/org/springframework/http/codec/support/CodecConfigurerTests.java
index 68e8d73db55..9f40db16792 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/support/CodecConfigurerTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/support/CodecConfigurerTests.java
@@ -91,6 +91,7 @@ class CodecConfigurerTests {
 
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultReaders() {
 		List<HttpMessageReader<?>> readers = this.configurer.getReaders();
 		assertThat(readers).hasSize(19);
@@ -116,6 +117,7 @@ class CodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultWriters() {
 		List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
 		assertThat(writers).hasSize(18);
@@ -140,6 +142,7 @@ class CodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultAndCustomReaders() {
 		Decoder<?> customDecoder1 = mock();
 		Decoder<?> customDecoder2 = mock();
@@ -188,6 +191,7 @@ class CodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultAndCustomWriters() {
 		Encoder<?> customEncoder1 = mock();
 		Encoder<?> customEncoder2 = mock();
diff --git a/spring-web/src/test/java/org/springframework/http/codec/support/ServerCodecConfigurerTests.java b/spring-web/src/test/java/org/springframework/http/codec/support/ServerCodecConfigurerTests.java
index 927b2aac5dc..0ee3cabc7fd 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/support/ServerCodecConfigurerTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/support/ServerCodecConfigurerTests.java
@@ -92,6 +92,7 @@ class ServerCodecConfigurerTests {
 
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultReaders() {
 		List<HttpMessageReader<?>> readers = this.configurer.getReaders();
 		assertThat(readers).hasSize(19);
@@ -117,6 +118,7 @@ class ServerCodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void defaultWriters() {
 		List<HttpMessageWriter<?>> writers = this.configurer.getWriters();
 		assertThat(writers).hasSize(19);
@@ -159,6 +161,7 @@ class ServerCodecConfigurerTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void maxInMemorySize() {
 		int size = 99;
 		this.configurer.defaultCodecs().maxInMemorySize(size);
diff --git a/spring-web/src/test/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilderTests.java b/spring-web/src/test/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilderTests.java
index 9b1398bf90e..bcd60f35c78 100644
--- a/spring-web/src/test/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilderTests.java
+++ b/spring-web/src/test/java/org/springframework/http/server/reactive/DefaultServerHttpRequestBuilderTests.java
@@ -98,6 +98,7 @@ class DefaultServerHttpRequestBuilderTests {
 		return argumentSet(description, headerMap, true);
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Arguments> headers() {
 		return Stream.of(
 				initHeader("Map", CollectionUtils.toMultiValueMap(new LinkedCaseInsensitiveMap<>(8, Locale.ENGLISH))),
diff --git a/spring-web/src/test/java/org/springframework/http/server/reactive/HeadersAdaptersTests.java b/spring-web/src/test/java/org/springframework/http/server/reactive/HeadersAdaptersTests.java
index aa7f58cf032..9456f6a932f 100644
--- a/spring-web/src/test/java/org/springframework/http/server/reactive/HeadersAdaptersTests.java
+++ b/spring-web/src/test/java/org/springframework/http/server/reactive/HeadersAdaptersTests.java
@@ -279,6 +279,7 @@ class HeadersAdaptersTests {
 	@interface ParameterizedHeadersTest {
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Arguments> headers() {
 		return Stream.of(
 				argumentSet("Map", CollectionUtils.toMultiValueMap(new LinkedCaseInsensitiveMap<>(8, Locale.ENGLISH))),
@@ -298,6 +299,7 @@ class HeadersAdaptersTests {
 	@interface ParameterizedPopulatedHeadersTest {
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Arguments> nativeHeadersWithCasedEntries() {
 		return Stream.of(
 				argumentSet("Netty", new Netty4HeadersAdapter(withHeaders(new DefaultHttpHeaders(), h -> h::add))),
diff --git a/spring-web/src/test/java/org/springframework/web/util/ContentCachingRequestWrapperTests.java b/spring-web/src/test/java/org/springframework/web/util/ContentCachingRequestWrapperTests.java
index 871e6fbb602..415a5df7372 100644
--- a/spring-web/src/test/java/org/springframework/web/util/ContentCachingRequestWrapperTests.java
+++ b/spring-web/src/test/java/org/springframework/web/util/ContentCachingRequestWrapperTests.java
@@ -34,6 +34,7 @@ import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
  * @author Brian Clozel
  * @author Stephane Nicoll
  */
+@SuppressWarnings("removal")
 class ContentCachingRequestWrapperTests {
 
 	protected static final String FORM_CONTENT_TYPE = MediaType.APPLICATION_FORM_URLENCODED_VALUE;
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpServer.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpServer.java
index a70981e0284..222e08cd250 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpServer.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpServer.java
@@ -29,6 +29,7 @@ import org.springframework.http.server.reactive.ReactorNetty2HttpHandlerAdapter;
  * @author Violeta Georgieva
  * @since 6.0
  */
+@SuppressWarnings("removal")
 public class ReactorNetty2HttpServer extends AbstractHttpServer {
 
 	private ReactorNetty2HttpHandlerAdapter reactorHandler;
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpsServer.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpsServer.java
index 5c3d5c2bac5..cbd384089e1 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpsServer.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/ReactorNetty2HttpsServer.java
@@ -31,6 +31,7 @@ import org.springframework.http.server.reactive.ReactorNetty2HttpHandlerAdapter;
  * @author Violeta Georgieva
  * @since 6.0
  */
+@SuppressWarnings("removal")
 public class ReactorNetty2HttpsServer extends AbstractHttpServer {
 
 	private ReactorNetty2HttpHandlerAdapter reactorHandler;
diff --git a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/UndertowHttpServer.java b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/UndertowHttpServer.java
index d021b2cdd2a..180e829c6d2 100644
--- a/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/UndertowHttpServer.java
+++ b/spring-web/src/testFixtures/java/org/springframework/web/testfixture/http/server/reactive/bootstrap/UndertowHttpServer.java
@@ -25,6 +25,7 @@ import org.springframework.http.server.reactive.UndertowHttpHandlerAdapter;
 /**
  * @author Marek Hawrylczak
  */
+@SuppressWarnings("removal")
 public class UndertowHttpServer extends AbstractHttpServer {
 
 	private Undertow server;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java b/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
index a09a707eb8f..88fbf4af0ac 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/function/client/DefaultWebClientBuilder.java
@@ -332,6 +332,7 @@ final class DefaultWebClientBuilder implements WebClient.Builder {
 				new DefaultWebClientBuilder(this));
 	}
 
+	@SuppressWarnings("removal")
 	private ClientHttpConnector initConnector() {
 		if (reactorNettyClientPresent) {
 			return new ReactorClientHttpConnector();
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RouterFunctions.java b/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RouterFunctions.java
index 50bdbac2889..9ebd9d9df41 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RouterFunctions.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RouterFunctions.java
@@ -272,8 +272,6 @@ public abstract class RouterFunctions {
 	 * {@link org.springframework.http.server.reactive.ServletHttpHandlerAdapter}</li>
 	 * <li>Reactor using the
 	 * {@link org.springframework.http.server.reactive.ReactorHttpHandlerAdapter}
-	 * <li>Undertow using the
-	 * {@link org.springframework.http.server.reactive.UndertowHttpHandlerAdapter}</li>
 	 * </ul>
 	 * <p>Note that {@code HttpWebHandlerAdapter} also implements {@link WebHandler},
 	 * allowing for additional filter and exception handler registration through
@@ -294,8 +292,6 @@ public abstract class RouterFunctions {
 	 * {@link org.springframework.http.server.reactive.ServletHttpHandlerAdapter}</li>
 	 * <li>Reactor using the
 	 * {@link org.springframework.http.server.reactive.ReactorHttpHandlerAdapter}</li>
-	 * <li>Undertow using the
-	 * {@link org.springframework.http.server.reactive.UndertowHttpHandlerAdapter}</li>
 	 * </ul>
 	 * @param routerFunction the router function to convert
 	 * @param strategies the strategies to use
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/WebSocketMessage.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/WebSocketMessage.java
index f5fd9939df1..8e7daa5fbc9 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/WebSocketMessage.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/WebSocketMessage.java
@@ -196,6 +196,7 @@ public class WebSocketMessage {
 	}
 
 
+	@SuppressWarnings("removal")
 	private static class ReactorNetty2Helper {
 
 		static WebSocketMessage retain(WebSocketMessage message) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/Netty5WebSocketSessionSupport.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/Netty5WebSocketSessionSupport.java
index 11634046234..908bffb247b 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/Netty5WebSocketSessionSupport.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/Netty5WebSocketSessionSupport.java
@@ -44,7 +44,10 @@ import org.springframework.web.reactive.socket.WebSocketSession;
  * @author Violeta Georgieva
  * @since 6.0
  * @param <T> the native delegate type
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public abstract class Netty5WebSocketSessionSupport<T> extends AbstractWebSocketSession<T> {
 
 	/**
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNetty2WebSocketSession.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNetty2WebSocketSession.java
index a567ab6a235..1c1825f7e88 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNetty2WebSocketSession.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/ReactorNetty2WebSocketSession.java
@@ -43,7 +43,10 @@ import org.springframework.web.reactive.socket.WebSocketSession;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class ReactorNetty2WebSocketSession
 		extends Netty5WebSocketSessionSupport<ReactorNetty2WebSocketSession.WebSocketConnection> {
 
@@ -133,7 +136,10 @@ public class ReactorNetty2WebSocketSession
 
 	/**
 	 * Simple container for {@link NettyInbound} and {@link NettyOutbound}.
+	 * @deprecated as of 6.2.18 with no replacement
 	 */
+	@Deprecated(since = "6.2.18", forRemoval = true)
+	@SuppressWarnings("removal")
 	public static class WebSocketConnection {
 
 		private final WebsocketInbound inbound;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketHandlerAdapter.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketHandlerAdapter.java
index 5fe77a4147a..e261483654c 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketHandlerAdapter.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketHandlerAdapter.java
@@ -42,7 +42,10 @@ import org.springframework.web.reactive.socket.WebSocketMessage.Type;
  * @author Violeta Georgieva
  * @author Rossen Stoyanchev
  * @since 5.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class UndertowWebSocketHandlerAdapter extends AbstractReceiveListener {
 
 	private final UndertowWebSocketSession session;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketSession.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketSession.java
index 834e6296a98..d7e79a69d38 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketSession.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/adapter/UndertowWebSocketSession.java
@@ -44,7 +44,9 @@ import org.springframework.web.reactive.socket.WebSocketSession;
  * @author Violeta Georgieva
  * @author Rossen Stoyanchev
  * @since 5.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class UndertowWebSocketSession extends AbstractListenerWebSocketSession<WebSocketChannel> {
 
 	public UndertowWebSocketSession(WebSocketChannel channel, HandshakeInfo info, DataBufferFactory factory) {
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/ReactorNetty2WebSocketClient.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/ReactorNetty2WebSocketClient.java
index 599463c94a2..6a99668fe4c 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/ReactorNetty2WebSocketClient.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/ReactorNetty2WebSocketClient.java
@@ -43,7 +43,9 @@ import org.springframework.web.reactive.socket.adapter.ReactorNetty2WebSocketSes
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class ReactorNetty2WebSocketClient implements WebSocketClient {
 
 	private static final Log logger = LogFactory.getLog(ReactorNetty2WebSocketClient.class);
@@ -119,6 +121,7 @@ public class ReactorNetty2WebSocketClient implements WebSocketClient {
 	}
 
 	@Override
+	@SuppressWarnings("removal")
 	public Mono<Void> execute(URI url, HttpHeaders requestHeaders, WebSocketHandler handler) {
 		String protocols = StringUtils.collectionToCommaDelimitedString(handler.getSubProtocols());
 		WebsocketClientSpec clientSpec = buildSpec(protocols);
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/UndertowWebSocketClient.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/UndertowWebSocketClient.java
index c5968151897..85d163d17a7 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/UndertowWebSocketClient.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/client/UndertowWebSocketClient.java
@@ -52,7 +52,10 @@ import org.springframework.web.reactive.socket.adapter.UndertowWebSocketSession;
  * @author Violeta Georgieva
  * @author Rossen Stoyanchev
  * @since 5.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class UndertowWebSocketClient implements WebSocketClient {
 
 	private static final Log logger = LogFactory.getLog(UndertowWebSocketClient.class);
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketService.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketService.java
index 6e1f3519db2..68275cd91f8 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketService.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/support/HandshakeWebSocketService.java
@@ -282,6 +282,7 @@ public class HandshakeWebSocketService implements WebSocketService, Lifecycle {
 	}
 
 
+	@SuppressWarnings("removal")
 	static RequestUpgradeStrategy initUpgradeStrategy() {
 		if (tomcatWsPresent) {
 			return new TomcatRequestUpgradeStrategy();
@@ -319,6 +320,7 @@ public class HandshakeWebSocketService implements WebSocketService, Lifecycle {
 			return new ReactorNettyRequestUpgradeStrategy();
 		}
 
+		@SuppressWarnings("removal")
 		public static RequestUpgradeStrategy forReactorNetty2() {
 			return new ReactorNetty2RequestUpgradeStrategy();
 		}
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNetty2RequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNetty2RequestUpgradeStrategy.java
index c08ad724f41..6c5ea9468fe 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNetty2RequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/ReactorNetty2RequestUpgradeStrategy.java
@@ -41,7 +41,10 @@ import org.springframework.web.server.ServerWebExchange;
  *
  * @author Violeta Georgieva
  * @since 6.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class ReactorNetty2RequestUpgradeStrategy implements RequestUpgradeStrategy {
 
 	private final Supplier<WebsocketServerSpec.Builder> specBuilderSupplier;
diff --git a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
index 8e411e6b58c..e76700b89c6 100644
--- a/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
+++ b/spring-webflux/src/main/java/org/springframework/web/reactive/socket/server/upgrade/UndertowRequestUpgradeStrategy.java
@@ -48,7 +48,10 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Rossen Stoyanchev
  * @author Brian Clozel
  * @since 5.0
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
+@SuppressWarnings("removal")
 public class UndertowRequestUpgradeStrategy implements RequestUpgradeStrategy {
 
 	@Override
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java
index fa0c661912d..675bc7cf4af 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/function/client/WebClientIntegrationTests.java
@@ -106,6 +106,7 @@ class WebClientIntegrationTests {
 	@interface ParameterizedWebClientTest {
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Arguments> arguments() {
 		return Stream.of(
 				argumentSet("Reactor Netty", new ReactorClientHttpConnector()),
@@ -194,6 +195,7 @@ class WebClientIntegrationTests {
 	}
 
 	@ParameterizedWebClientTest
+	@SuppressWarnings("removal")
 	void applyAttributesToNativeRequest(ClientHttpConnector connector) {
 		startServer(connector);
 		prepareResponse(response -> {});
@@ -948,6 +950,7 @@ class WebClientIntegrationTests {
 	}
 
 	@ParameterizedWebClientTest
+	@SuppressWarnings("removal")
 	void statusHandlerSuppressedErrorSignalWithFlux(ClientHttpConnector connector) {
 
 		// Temporarily disabled, leads to io.netty5.buffer.BufferClosedException
diff --git a/spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractReactiveWebSocketIntegrationTests.java b/spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractReactiveWebSocketIntegrationTests.java
index d4c8a75c5a0..f8dd9bf0aa1 100644
--- a/spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractReactiveWebSocketIntegrationTests.java
+++ b/spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractReactiveWebSocketIntegrationTests.java
@@ -93,6 +93,7 @@ abstract class AbstractReactiveWebSocketIntegrationTests {
 	@interface ParameterizedWebSocketTest {
 	}
 
+	@SuppressWarnings("removal")
 	static Stream<Object[]> arguments() throws IOException {
 
 		List<Named<WebSocketClient>> clients = List.of(
@@ -214,6 +215,7 @@ abstract class AbstractReactiveWebSocketIntegrationTests {
 	}
 
 	@Configuration
+	@SuppressWarnings("removal")
 	static class ReactorNetty2Config extends AbstractHandlerAdapterConfig {
 
 		@Override
@@ -233,6 +235,7 @@ abstract class AbstractReactiveWebSocketIntegrationTests {
 
 
 	@Configuration
+	@SuppressWarnings("removal")
 	static class UndertowConfig extends AbstractHandlerAdapterConfig {
 
 		@Override
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/UndertowRequestUpgradeStrategy.java b/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/UndertowRequestUpgradeStrategy.java
index e1623fe9d7c..a1bbefb12ff 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/UndertowRequestUpgradeStrategy.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/server/standard/UndertowRequestUpgradeStrategy.java
@@ -34,7 +34,9 @@ import jakarta.websocket.server.ServerEndpointConfig;
  * @author Juergen Hoeller
  * @since 4.0.1
  * @see io.undertow.websockets.jsr.ServerWebSocketContainer#doUpgrade
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class UndertowRequestUpgradeStrategy extends StandardWebSocketUpgradeStrategy {
 
 	private static final String[] SUPPORTED_VERSIONS = new String[] {"13", "8", "7"};
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java b/spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java
index 9bc90ef0078..f5ae86a275b 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/server/support/AbstractHandshakeHandler.java
@@ -403,6 +403,7 @@ public abstract class AbstractHandshakeHandler implements HandshakeHandler, Life
 	}
 
 
+	@SuppressWarnings("removal")
 	private static RequestUpgradeStrategy initRequestUpgradeStrategy() {
 		if (tomcatWsPresent) {
 			return new TomcatRequestUpgradeStrategy();
diff --git a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/UndertowXhrTransport.java b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/UndertowXhrTransport.java
index c998e6ef440..10889cbe26d 100644
--- a/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/UndertowXhrTransport.java
+++ b/spring-websocket/src/main/java/org/springframework/web/socket/sockjs/client/UndertowXhrTransport.java
@@ -88,7 +88,9 @@ import org.springframework.web.socket.sockjs.frame.SockJsFrame;
  * @author Rossen Stoyanchev
  * @since 4.1.2
  * @see org.xnio.Options
+ * @deprecated as of 6.2.18 with no replacement
  */
+@Deprecated(since = "6.2.18", forRemoval = true)
 public class UndertowXhrTransport extends AbstractXhrTransport {
 
 	private static final AttachmentKey<String> RESPONSE_BODY = AttachmentKey.create(String.class);
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/AbstractWebSocketIntegrationTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/AbstractWebSocketIntegrationTests.java
index 41788a35c10..690449df825 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/AbstractWebSocketIntegrationTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/AbstractWebSocketIntegrationTests.java
@@ -198,6 +198,7 @@ public abstract class AbstractWebSocketIntegrationTests {
 
 
 	@Configuration(proxyBeanMethods = false)
+	@SuppressWarnings("removal")
 	static class UndertowUpgradeStrategyConfig extends AbstractRequestUpgradeStrategyConfig {
 
 		@Override
diff --git a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/client/UndertowSockJsIntegrationTests.java b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/client/UndertowSockJsIntegrationTests.java
index 1986a65988b..c535d417171 100644
--- a/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/client/UndertowSockJsIntegrationTests.java
+++ b/spring-websocket/src/test/java/org/springframework/web/socket/sockjs/client/UndertowSockJsIntegrationTests.java
@@ -29,6 +29,7 @@ import org.springframework.web.socket.server.standard.UndertowRequestUpgradeStra
 /**
  * @author Brian Clozel
  */
+@SuppressWarnings("removal")
 class UndertowSockJsIntegrationTests extends AbstractSockJsIntegrationTests {
 
 	@Override