The update in TSML Ver 1.3 adds a specific count of the number of time steps in a timeseries, or each homogenous (regularly spaced) segment of an irregularly spaced whole timeseries. It is an optional TimeseriesMetadata property of type Integer for both the TVP and Domain-Range encodings. TimeseriesMetadata is of type "tsml:TimeseriesMetadataType" and the additional property will be added to this type.
Timeseries SWG Request For Change 577 (Count).pptx