“In this case, the federal government prohibited us from sharing any information.”
Foreign and U.S. agencies have been asking Apple and Google for push notification metadata to tie anonymous messaging app users to real accounts. Apple only admits it after Senator Ron Wyden’s letter made the method public. Nobody can say how long the requests have gone on. Apple’s advice to developers is to encrypt their payloads, but the metadata showing which apps ping you and how often stays readable. Every encrypted messenger still phones home through Apple or Google.