Glue WS Client vs WS-Stack client

Is there a reason why two SOAP client libraries are being supported to create web service connectors in CAF?
AFAIK, Glue and WS-Stack are two libraries to do the same thing. If that is true, then why SoftwareAG is supporting both of them?
Does WS-stack have any special advantages over glue?

Hello Prasad,

Glue will be deprecated soon after 10.0 release. These libraries will not be available after this release but applications built using Glue will be supported for a while and after that they will have to replace their implementations with WS stack.

Thanks, Srikanth. Any technical differences between them that made SoftwareAG decide on deprecating Glue?