Recently, the new Planck Cosmic Microwave Background (CMB) measurements have greatly improved our knowledge of the Universe. Nevertheless the dark component of the radiation content of the Universe (coined dark radiation) remains an unsolved case and its existence is strongly dependent on the external data sets included in the analysis and on the assumed cosmological model. For instance, the discrepancy between the Planck results and the Hubble Space Telescope ones in the matter of the value of the Hubble constant can be reduced at the expenses of the standard ΛCDM model which must be enlarged including extra relativistic degrees of freedom, i.e. dark radiation. This dark-radiation case is extremely important because it can represent the cosmological counterpart to the sterile neutrinos hinted at by the short-baseline experiments. Here we update the cosmological constraints on sterile neutrinos using Planck CMB data, the Hubble Space Telescope measurements and the matter power spectrum extracted from the Data Release 9 (DR9) of the CMASS sample of galaxies. Furthermore, we assume an extended cosmological scenario with a varying lensing amplitude. If the new Planck data are analyzed in the framework of this cosmological model, we find an evidence of additional massive species above the 2σ c.l.