...

Are you talking about tracking changes on your artifacts or on having explicit versions each time you change an artifact?

How JIRA handles versioning

As preliminary information, JIRA issues are assigned to a given version, by specifying the "Fix Version" field. 

...

If you make changes in some of the attributes of a issue, it gets tracked in the History changes; however, there is no increment in the version (not in any other field) of the requirement because it is used for another purpose: to tell for which version you're delivering it. 

How does Xray handle "versioning" of Test cases

Versioning of Tests work in the same way as versioning of other issue types in JIRA. Since Xray's Tests are JIRA issues, we follow the same approach so your users work in the same manner.

...