When porting aTalk to use smack 4.5.0 release, following is my observations on smack 4.5.0 libriaries update.
a. FullyQualifiedElement is deprecated and replaced by XmlElement class.
b. Attempt to port all usages and extends of ExtensionElement to XmlElement.
In follow suite, aTalk also tries to replace usages/extends of ExtensionElement to XmlElement. However there was some limitations in doing so; it was found that some of smack 4.5.0 sources still contain a mix of both ExtensionElement and XmlElement. Examples in the following files.
smack-core:
StanzaBuilder, Stanza, StanzaView
smack-extensions:
ChatStateManager, StreamInitiation, JingleContentDescription, JingleContentDescription(NamedElement), JingleIBBTransport
Appreciate your team can look into these files, possiblely to make the necessary changes.