AS3 (Applicability Standard 3) is the draft specification standard that enables vendor applications to communicate EDI (or other data such as XML) over the Internet using File Transfer Protocol (FTP).
AS3 is not the next version of AS2 as it offers its own unique features and provides security for the transport payload through digital signatures and data encryption. It also ensures reliable delivery through the use of receipts. AS3 only specifies how to transport data and not how to validate or process it. As with both AS1 and AS2, AS3 was developed as part of the IETF EDI-INT Work Group.
All of these standards have their own merits and uses in today's marketplace. Adoption of one or more standards by a specific industry depends on utilizing the one that best suits that industry's customer requirements.