* Installer has to work on EAP 6.x too.
I suppose you only mean it for adapter, not for the server?
Currently auth-server support is only part of wildfly-subsystem, which ATM also contains
EAP 6.x support which makes it use deprecated subsystem APIs. Keeping things that way is
not a good foundation for the future on top of WildFly 10.
The server / adapter subsystem split will result in wildfly-subsystem become
wildfly-server-subsystem, and wildfly-adapter-subsystem. In order to keep things clean we
would have to extract EAP 6.x support out into another module.
There is wildfly-as7-subsystem which currently only contains adapter support. Since EAP
6.x is API compatible with AS7 it seems a better place for EAP 6.x parts.