Probably related to Smack 4 update. Maybe even this was removed from Smack for security reasons. Needs an investigation.
it looks like this works with when querying other clients. It appears to be an issue with spark replying to queries. The time query looks like its being sent correct, but the version does not. no idea how to fix this or what to do next, but maybe this will help someone.
<error type="modify"><not-acceptable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/></error></iq>
likely an issue with org.jivesoftware.sparkimpl.plugin.jabber.JabberVersion.java and/or org.jivesoftware.sparkimpl.plugin.jabber.VersionViewer.java
Merged https://github.com/igniterealtime/Spark/pull/300
Still can't get client version of another Spark 2.8.x client. Shows loading indicator though.