|Feature users and use cases=This change will affect all Thunderbird users who make use of the address book.
[[Modern_Address_Book_Use_CasesThunderbird/Modern_Address_Book/Use_Cases|Here are the current series of use cases.]]
|Feature non-goals=At this point, we're not going to let contact providers push changes to other contact providers through Thunderbird. So, in other words, if a contact provider X sends an updated field, Thunderbird will not update this field for other contact providers.