Incomplete Stats in OpenML Features using Java API #35

Using the latest Java API (ver. 1.0.13 from Maven), we are facing an issue with the dataFeatures class methods to get some statistics about the features in the datasets. Whenever we call a method to retrieve statistics about the features (e.g. getNumberOfDistinctValues() ), we get a Null value. For example, when called using dataset_id = 967 or 21.

Are those methods to retrieve such statistics about features fully implemented in the current version of the API or are they still under development and shouldn't be used?