The current version of JATS is 1.4. Like all versions in the 1.X line, it is fully backwards compatible with all previous versions of JATS. This means that any document valid to one of the JATS profiles (Archiving, Publishing, Authoring) in any of the previous versions of JATS will be valid to the current version. The JATS Committee has further committed to the position that all previous valid JATS 1.X documents will be valid to future 1.x versions of that profile of JATS.

While there has been discussion of what a 2.0 version of JATS might look like, and what infelicities in JATS might be fixed if /when we can tidy up by removing structures that are no longer optimal, JATS 2.0 is in the indefinite future. So, accommodation of multilingual articles had to be built into JATS 1.X, and thus in a way that articles that were created before this was developed would be valid and would have no changes to their meanings when used with a schema that included the multi-language mechanism.