Upgrading to ConfigMgr R2 and MDT 2013
From the archive (2013). Written for the tools of the time, so some details may be out of date.
Johan Arwidmark apparently has more time on his hands than I do :) He beat me to writing a blog post for upgrading to R2 and MDT 2013.
Go over to his post here for an excellent post on the steps required for the upgrades and a few “gotchas” to be aware of.