We consider a Maintenance Release of JSR 385 in the next two or three months, most likely after the JCP EC elections and new or reelected members taking their seats.
There are no real additions to the API except MeasurementError, which is to move from the RI for consistency reasons. It has no impact on the TCK but to throw a simple Error has been a bad practice in some places, therefore throwing a MeasurementError helps to solve that. It also helps to streamline a few specialized Error classes used e.g. for formatting and parsing.
There are a few minor improvements, adding an isEquivalentTo() method to both Unit and Quantity and cleaning up elements or methods that were deprecated before.
While MR1 won't justify a first digit version jump (it's intended as 2.1) there should be room for such improvement and the new elements have been around for over 2 years with another 4-5 JDK generations.
The dynamic annotation resolution e.g. in ServiceProvider shall support Jakarta Inject and Annotations under the new namespace, while all TCK or implementation modules that used the DI JSR before will also be upgraded to Jakarta Inject now.