diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java
index 4e96a626bc..1d4d74bb12 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpClientUpgradeHandler.java
@@ -261,7 +261,7 @@ public class HttpClientUpgradeHandler extends HttpObjectAggregator implements Ch
             builder.append(part);
             builder.append(',');
         }
-        builder.append(HttpHeaderNames.UPGRADE);
+        builder.append(HttpHeaderValues.UPGRADE);
         request.headers().set(HttpHeaderNames.CONNECTION, builder.toString());
     }
 }
diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaderValues.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaderValues.java
index 9c75473acc..b06fad5716 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaderValues.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpHeaderValues.java
@@ -193,9 +193,9 @@ public final class HttpHeaderValues {
      */
     public static final AsciiString TRAILERS = new AsciiString("trailers");
     /**
-     * {@code "Upgrade"}
+     * {@code "upgrade"}
      */
-    public static final AsciiString UPGRADE = new AsciiString("Upgrade");
+    public static final AsciiString UPGRADE = new AsciiString("upgrade");
     /**
      * {@code "websocket"}
      */