You can always send and receive messages no matter what XEPs are supported. Not that that is a problem in practice. There is a fairly well established subset of XEPs that everyone supports.
Unless you want to encrypt said messages. But I guess insecure communication beats no communication at all. (I also never had much luck with voice and video calls using XMPP.)
https://xmpp.org/extensions/xep-0479.html
https://compliance.conversations.im/