What happened to the custom date format in D7?
Under Home » Administration » Configuration » Regional and language
where you find the Long, Medium, and Short options for Date Type, when you go to Add Date Type, there used to be an option to use the PHP codes to create a custom date type (ie: F, Y for Month, Year > April, 2001).
Now when I click there, I just get a listing of the formats already available, with no option to customize.