= 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 `HTTPS` listener.
* Adds support for `HTTP2`.
* Sets the default `Server` response header.
* Sets the default `HTTP Invoker`.

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.add-undertow-https-listener.skip` | If set to `true`, the tool does not sets the default `HTTPS` listener.
| `subsystem.undertow.update.enable-http2.skip` | If set to `true`, the tool does not add support for `HTTP2`.
| `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-http-invoker.skip` | If set to `true`, the tool does not sets the default `HTTP Invoker`.
|===

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

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