This Technical Specification constitutes the functional specification of a secure electronic postal service, referred to as the postal registered electronic mail or PReM service. PReM provides a trusted and certified electronic mail exchange between mailer, postal operators and addressee/mailee. In addition, evidence of corresponding events and operations within the scope of PReM will be generated and archived for future attestation. The PReM service is defined by reference to the concepts, schemas and operations defined in CEN/TS 15121-1:2011. It utilises six SePS operational verbs (CheckIntegrity, LogEvent, Postmark, RetrieveResults, Sign and Verify) and the five additional server-side operational verbs (SendMessagetoDestination, Subscribe Notification, UnscbscribeNotification, RejectMessage and ReceiveNotification) to fulfil the operational requirements of a PReM System. Return of Investment (ROI), market potential, revenues model, business plan and pricing policy are outside the scope of this functional specification. Postal operators are advised to make the necessary marketing study and research prior to considering leasing, procuring or developing such a PReM system in accordance with this functional specification.