There's at least two books I know of that cover upgrading to rails 4. Here's one: http://www.upgradingtorails4.com/ http://www.upgradingtorails4.com/ Full disc

There's at least two books I know of that cover upgrading to rails 4. Here's one: http://www.upgradingtorails4.com/ http://www.upgradingtorails4.com/ Full disclosure: I'm friends and work with Andy and he's super smart and I'm not getting a kickback. :)