Hi Tich,
We deprecated the AppUpdater / AppLauncher in DevForce Classic in favor of ClickOnce. We never removed it altogether though, so it is still supported, although as you've found there's little to no documentation.
I've attached a zip containing some documentation and sample files, but here's a brief overview:
The format of the version.xml file is simple -
<?xml version="1.0" encoding="utf-8" ?>
<version updating="false" value="1.0.0.0"/>
You'll have one version file on your client and one on the server. Your application calls AppUpdater.Update() at startup, and this in turn checks the version numbers from both client and server version.xml files to determine if an update is required. If so, the files in the server folder are downloaded to the client. The download is using WebDav, which does have special setup and security requirements (which I can't find documented anywhere at the moment).
Your client-side ibconfig file will contain an <appUpdater> section:
<appUpdater>
<updateURL>http://someserver/myupdatesite</updateURL>
<versionFileName>version.xml</versionFileName>
<appLauncher>AppLauncher.exe</appLauncher>
</appUpdater>
The important element here is the updateURL, which is the URL to your web site hosting the application updates. The AppLauncher.exe is provided with the DevForce installation, and should be copied to your application deployment folder.