= Update the undertow Subsystem

In addition to migrating the *web* subsystem to {server-target-productName}, the JBoss Server Migration Tool adds the following functionality provided by the new *undertow* subsystem, which is configured in the {server-target-productName} default server configurations.

* Sets the default `HTTP Listener` redirect socket.
* Adds support for Java EE 7 `Websockets`.
* Sets the default `Server` response header.
* Sets the default `X-Powered-By` response header.

By default, the tool automatically updates any *undertow* subsystem configuration to include these changes.
If you prefer, you can configure the environment properties to customize the process of updating the *undertow* subsystem configuration.

|===
| Property Name |Property Description

| `subsystem.undertow.update.skip` | If set to `true`, the tool skips the update of the *undertow* subsystem.
| `subsystem.undertow.update.set-default-http-listener-redirect-socket.skip` | If set to `true`, the tool does not set the default `HTTP Listener` redirect socket.
| `subsystem.undertow.update.add-undertow-websockets.skip` | If set to `true`, the tool does not add support for WebSockets.
| `subsystem.undertow.update.add-response-header.server-header.skip` | If set to `true`, the tool does not set the default `Server` response header.
| `subsystem.undertow.update.add-response-header.x-powered-by-header.skip` | If set to `true`, the tool does not set the default `X-Powered-By` response header.
|===

Upon successful migration of a *undertow* subsystem configuration, you should see the following message in the console:

[source,options="nowrap"]
----
 INFO  Subsystem undertow updated.
----
