From Wikipedia: "FISA was modified by section 215 (Access to records and other items under the Foreign Intelligence Surveillance Act) to allow the Director of

From Wikipedia: "FISA was modified by section 215 (Access to records and other items under the Foreign Intelligence Surveillance Act) to allow the Director of the FBI (or an official designated by the Director, so long as that official's rank is no lower than Assistant Special Agent in Charge) to apply for an order to produce materials that assist in an investigation undertaken to protect against international terrorism or clandestine intelligence activities. The act specifically gives an example to clarify what it means by "tangible things": it includes "books, records, papers, documents, and other items". So yes, they have to provide access to the records they have, which is a big reason why end-to-end crypto is rolled out in the first place. If the records don't contain any decryption keys, the content of messages is safe. All other metadata (sender, receiver, timestamp, message size) is not, since it's needed for delivery.