There is no upgrade guide from 4 to 7,so I did from 4.2 to 5,from 5 to 5.1, from 6 to 6.1 and then to 7.
I actually found a bug that broke my app at version 6 that was resolved in 6.1,so technically my tests were not passing in version 6 and I did an "unsafe upgrade" to version 6.1