In the late 1990s, the ITU-T consolidated recommendations F.400 and X.400 and published the ITU-T F.400/X.400 (06/1999) recommendation "Message handling system and service overview".
Na konci 90. let 20. století ITU-T sjednotila doporučení F.400 a X.400 a publikovala ITU-T F.400/X.400 (06/1999) doporučení „Message handling system and service overview“.