EPSG:4979 is the same as EPSG:4326, only with a third axis for the height.

PostGIS does not care that the CRS defines a third axis (the PROJ.4 text does not even mention it); it is always possible to use Z coordinates, regardless of how the CRS is defined.

So all reprojections will work, with the same accuracy as the normal EPSG:4326 (WGS84 lat/lon).

Too check if a function can work with Z coordinates, see the "2.5D" column in the PostGIS Function Support Matrix.

EPSG:4979 is the same as EPSG:4326, only with a third axis for the height.

PostGIS does not care that the CRS defines a third axis (the PROJ.4 text does not even mention it); it is always possible to use Z coordinates, regardless of how the CRS is defined.

So all reprojections will work, with the same accuracy as the normal EPSG:4326 (WGS84 lat/lon).

To check if a function can work with Z coordinates, see the "2.5D" column in the PostGIS Function Support Matrix.