In Application Server 8.1, domain.xml is the main server configuration file. In Application Server 7, the main server configuration file was server.xml. The DTD file of domain.xml is found in lib/dtds/sun-domain_1_1.dtd. The upgrade tool included in Application Server 8.1 can be used to migrate the server.xml from Application Server 7 to domain.xml for Application Server 8.1.
The lib/dtds/sun-domain_1_1.dtd file for Application Server 8.1 is fully backward compatible with the corresponding file for Application Server 8, sun-domain_1_0.dtd.
In general, the configuration file formats are not backward compatible. The following configuration files are not supported:
server.xml (replaced with domain.xml)