To FDI or Not to FDI? That is the Question.
One of the most asked questions on the FieldComm Group Support Portal from members is a variation of "I want to update and register my new DD. Do I also need to supply an FDI Device Package with my registration package?"

As with most things in the FieldComm Group technology standards the answer is.... it depends!
Here are some additional references to help you get started on a test and registration campaign: 
Knowledgebase - Registration & Testing Services 

Fun Fact: "To (do something) or not to (do something), that is the question" is an expression derived from the famous line in William Shakespeare's play Hamlet, "To be, or not to be, that is the question." Used to express one's indecision or hesitation about doing something, it's usually used humorously, especially as a rhyming pun on "be."