upgrade of weblogic server becomes much easier nowadays.
Once installed weblogic server 11g, (download from oracle website). after finish installation, coming to quick starts, there are options, either to create new domains, or update existing domains with old version.
choosing the update option, just click and follow steps, most commonly, it’s naturally, smoothly done well.
from http://www.oracle.com/technetwork/middleware/fusion-middleware/downloads/index.html
