Last May 20, 2019 became effective the redefinition of the International System of Units (SI). In the new definition the kilogram (kg), kelvin (K) and mol are defined using numerical values of the Planck constant (h), the Boltzmann constant (kB) and the Avogadro constant (NA), respectively. A SI brochure is available from the Bureau International des Poids et Mesures. Farewell to the venerable kg prototype made of Pt/Ir.
In the picture above the new SI (graphic by Emilio Pisanti in wikipedia).