XMPP Instant messaging application based on the ‘Extensible Messaging and Presence Protocol’ (XMPP), formerly known as Jabber that enables you to connect with other people over the Internet will begin refusing unencrypted connections as from today. The move is in the response to the revelations of mass surveillance conducted by the US National Security Agency (NSA) revealed by former contractor Edward Snowden that triggered a large-scale movement worldwide towards deploying encryption across all the Digital Services. In addition to the official Jabber client software, you can also download other popular free instant messaging clients applications such as Pidgin, Gajim, Psi, Miranda, IM+ Xabber or Mozilla Thunderbird.
Source: https://thehackernews.com/2014/05/xmpp-makes-encryption-mandatory-for.html