Application-Layer Protocol Negotiation (ALPN) is a Transport Layer Security (TLS) extension for application layer protocol negotiation. ALPN allows the application layer to negotiate which protocol should be performed over a secure connection in a manner which avoids additional round trips and which is independent of the application layer protocols.
On April 11, 2012, Google's Adam Langley announced that TLS False Start will be disabled in Google Chrome from version 20 onward except for websites with the Next Protocol Negotiation (NPN) extension.
On March 20, 2013, Google's Adam Langley reported that NPN will be replaced with a reworked version, ALPN. On July 11, 2014, ALPN has been published as RFC 7301.