2005-07-12 2017-04-24 Labels beginning with X are reserved for private use. All others: Standards Track RFC or an IESG-approved experimental protocol. All capability labels in the registry MUST consist only of US-ASCII letters, digits, and the characters dot (".") and dash ("-"), and MUST begin with a letter other than X. They MUST be at least three characters. AUTHINFO Authentication COMPRESS Supported compression algorithms HDR Batched header retrieval IHAVE IHAVE command available IMPLEMENTATION Server implementation-specific information LIST LIST command variants MODE-READER Mode-switching server and MODE READER command available NEWNEWS NEWNEWS command available OVER Overview support POST POST command available READER Reader commands available SASL Supported SASL mechanisms STARTTLS Transport layer security STREAMING Streaming feeds VERSION Supported NNTP versions First Come First Served NNTP compression algorithms are named by strings from 1 to 20 characters in length consisting of uppercase letters, digits, hyphens, and/or underscores. DEFLATE COMMON Mandatory to implement IESG