JTA 1.3 is completed so it can't go there.  Release 1.3 is used to remove the three javax.transaction.xa.* classes that duplicate the classes owned by Java SE.  Note that the javax.transaction.* classes have been removed from Java SE 11 so there is no longer an overlap between Java SE and Java EE for the transaction API classes.

I realize this isn't getting to the heart of your request but just clarifying what is happening with respect to releases of the API jar file.