diff --git a/codec-http2/src/main/java/io/netty/handler/codec/http2/CleartextHttp2ServerUpgradeHandler.java b/codec-http2/src/main/java/io/netty/handler/codec/http2/CleartextHttp2ServerUpgradeHandler.java
index c70b343920..fe9353b92d 100644
--- a/codec-http2/src/main/java/io/netty/handler/codec/http2/CleartextHttp2ServerUpgradeHandler.java
+++ b/codec-http2/src/main/java/io/netty/handler/codec/http2/CleartextHttp2ServerUpgradeHandler.java
@@ -18,7 +18,6 @@ package io.netty.handler.codec.http2;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.channel.ChannelHandler;
-import io.netty.channel.ChannelHandlerAdapter;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.http.HttpServerCodec;
@@ -39,7 +38,7 @@ import static io.netty.util.internal.ObjectUtil.checkNotNull;
  * prior knowledge or not.
  */
 @UnstableApi
-public final class CleartextHttp2ServerUpgradeHandler extends ChannelHandlerAdapter {
+public final class CleartextHttp2ServerUpgradeHandler extends ByteToMessageDecoder {
     private static final ByteBuf CONNECTION_PREFACE = unreleasableBuffer(connectionPrefaceBuf());
 
     private final HttpServerCodec httpServerCodec;
@@ -66,36 +65,33 @@ public final class CleartextHttp2ServerUpgradeHandler extends ChannelHandlerAdap
     @Override
     public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
         ctx.pipeline()
-           .addBefore(ctx.name(), null, new PriorKnowledgeHandler())
-           .addBefore(ctx.name(), null, httpServerCodec)
-           .replace(this, null, httpServerUpgradeHandler);
+                .addAfter(ctx.name(), null, httpServerUpgradeHandler)
+                .addAfter(ctx.name(), null, httpServerCodec);
     }
 
     /**
      * Peek inbound message to determine current connection wants to start HTTP/2
      * by HTTP upgrade or prior knowledge
      */
-    private final class PriorKnowledgeHandler extends ByteToMessageDecoder {
-        @Override
-        protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
-            int prefaceLength = CONNECTION_PREFACE.readableBytes();
-            int bytesRead = Math.min(in.readableBytes(), prefaceLength);
+    @Override
+    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
+        int prefaceLength = CONNECTION_PREFACE.readableBytes();
+        int bytesRead = Math.min(in.readableBytes(), prefaceLength);
 
-            if (!ByteBufUtil.equals(CONNECTION_PREFACE, CONNECTION_PREFACE.readerIndex(),
-                                    in, in.readerIndex(), bytesRead)) {
-                ctx.pipeline().remove(this);
-            } else if (bytesRead == prefaceLength) {
-                // Full h2 preface match, removed source codec, using http2 codec to handle
-                // following network traffic
-                ctx.pipeline()
-                   .remove(httpServerCodec)
-                   .remove(httpServerUpgradeHandler);
+        if (!ByteBufUtil.equals(CONNECTION_PREFACE, CONNECTION_PREFACE.readerIndex(),
+                in, in.readerIndex(), bytesRead)) {
+            ctx.pipeline().remove(this);
+        } else if (bytesRead == prefaceLength) {
+            // Full h2 preface match, removed source codec, using http2 codec to handle
+            // following network traffic
+            ctx.pipeline()
+                    .remove(httpServerCodec)
+                    .remove(httpServerUpgradeHandler);
 
-                ctx.pipeline().addAfter(ctx.name(), null, http2ServerHandler);
-                ctx.pipeline().remove(this);
+            ctx.pipeline().addAfter(ctx.name(), null, http2ServerHandler);
+            ctx.pipeline().remove(this);
 
-                ctx.fireUserEventTriggered(PriorKnowledgeUpgradeEvent.INSTANCE);
-            }
+            ctx.fireUserEventTriggered(PriorKnowledgeUpgradeEvent.INSTANCE);
         }
     }