Do you mean deploy version 2 without shutting down version 1? I ask because you do not shut down the "server" (WebLogic Server) for a war deployment (although that seemed to work with an old WLS version, maybe 6 or 7).
For information about application versioning, see the documentation. You do not mention a version, so I am just including the first one that came up in my google search.
WebLogic application versioning
Quote from that :
For example, the following manifest file content describes an application with version “v920.beta”:
Manifest-Version: 1.0
Created-By: 1.4.1_05-b01 (Sun Microsystems Inc.)
Weblogic-Application-Version: v920.beta