We have a Liferay installation currently running on 5.2.3. I have upgraded it to 6.0.6. I can't do a complete test because of a classloader bug that prevents me from deploying our plug-in to 6.0.6, but it appears to be fine. I can login as the portal admin and upgrade permissions to algorithm 6.
When I upgrade from 6.0.6 to 6.1.1, the current portal configuration is lost. No matter what I do, I wind up at the initial Liferay configuration page. Even logging in using a valid user sends me back to the initial configuration page. It shouldn't be asking me to configure it, it should be configured already.