The Websites service in OS X Server on Mavericks and Mountain Lion has different configuration options than the Web service in Lion Server and Mac OS X Server v10.6. Learn how these settings will be affected when you upgrade.
SSL (Lion Server and Mac OS X Server v10.6)
In Lion Server and Mac OS X Server v10.6, SSL was not enabled for the default web site. But in Lion Server, certain web-based services such as Podcast Producer that required SSL were supported via a "shadow" site mechanism that was not visible to administrators unless they manually modified web config files; that mechanism is removed in Mountain Lion Server app.
In OS X Server (Mavericks and Mountain Lion), there are two default sites, neither of which can be deleted: The "Server Website" and "Server Website (SSL)". Whether or not you configured the default site with SSL in Lion Server or Mac OS X Server v10.6, you will see the two default sites in Server app on Mavericks or Mountain Lion. Server app allows selection of a certificate for the SSL site but does not allow a selection of "none". The upgrade/migration tools move aside and deactivate the configuration files for any Lion Server shadow sites, and make an effort to map old sites into the new scheme. (Although you cannot delete the default website, you can use redirects on the default website to forward it to the default SSL website)
If you previously enabled SSL for websites in Lion Server or Mac OS X Server v10.6, SSL certificate pass phrases in the previous system's Keychain may not be retained when upgrading to OS X Server (Mavericks or Mountain Lion). If this happens, websites that relied on SSL certificates from the previous system cannot function in the new system, which may prevent all web-related services from responding. To resolve this, use Server app to delete any Website references to old SSL certificates.
Realms (Mac OS X Server v10.6)
Realms in Mac OS X Server v10.6 allow restriction to one or more specific users and one or more specific groups, with control of the degree of access and type of authentication. Realms in OS X Server (Mavericks and Mountain Lion) are simplified, allowing only restriction to access by a specific group, with digest authentication. In general, Mac OS X Server v10.6 Web realms will need to be reconfigured in Server app after upgrade or migration, though certain realms settings are preserved if they map cleanly to the new Server interface.
Wiki/Blog (Mac OS X Server v10.6)
Wiki and Blog are configurable on a per-site basis in Mac OS X Server v10.6, but not in OS X Server (Mavericks and Mountain Lion). These per-site settings are dropped during upgrade or migration.
Mobile Access (Mac OS X Server v10.6)
The Mobile Access service was removed in Lion Server and is no longer a feature of OS X Server. Its configuration is removed during upgrade or migration.
Other Server Admin Web Settings (Mac OS X Server v10.6)
Besides Realms and Wiki/Blog settings, several other Web settings configurable in Server Admin in Mac OS X Server v10.6, such as mime types, forward proxies, and reverse proxies, are either not exposed or are significantly revised in OS X Server (Mavericks or Mountain Lion). The upgrade/migration tools make an effort to preserve such settings but in general such settings may not survive mapping to the new configuration scheme.
Both OS X and OS X Server use the Apache HTTP server. In OS X Lion and Mac OS X v10.6, Apache could be enabled by turning on Personal Web Sharing in the Sharing pane of System Preferences. This option is no longer available in OS X Mavericks or Mountain Lion, although the underlying Apache software is still included. For more information, see this article.