I recently had a colleague, Robert, stop by my desk and with a question about the compatibility level of a database. Essentially, he was interested in upgrading a database’s compatibility level but at the same time have the ability to down grade it if issues were found. Robert had a concern that if we had to downgrade, this action would impact the database internal structure or version.
I know that this is an old topic since I found a post from by Jonathan Kehayias (B|T) that talks about the exact same thing, but I think that it’s worth repeating. Paul Randal (B|T) also has one here.