Wikipedia tells me that iChat was XMPP-based, but was discontinued in 2012 and replaced with iMessage, which is based on Apple Push Notifications and not XMPP.

Wikipedia tells me that iChat was XMPP-based, but was discontinued in 2012 and replaced with iMessage, which is based on Apple Push Notifications and not XMPP. Google has also discontinued Hangouts and who knows what you're supposed to use now. Their chat stuff has been so chaotic I really can't keep track. (Allo? Duo? Plus? Google Talk? Wave? Chat?)