The Department for Financial Services (DFS) has reached agreement  with four US banks regulating their use of secure private messaging app Symphony. As a condition of the agreement, the DFS has required the retention of copies of all communications for seven years and additionally required the banks to store duplicate copies of the decryption keys to  their messages with independent custodians. This is the first time a US regulator has required external storage of decryption keys.

DFS Press Release