Long: no-alpn Tags: HTTP/2 Protocols: HTTPS Added: 7.36.0 See-also: no-npn http2 Requires: TLS Help: Disable the ALPN TLS extension --- Disable the ALPN TLS extension. ALPN is enabled by default if libcurl was built with an SSL library that supports ALPN. ALPN is used by a libcurl that supports HTTP/2 to negotiate HTTP/2 support with the server during https sessions.