The importance of GW170817 for equation of state constraints was immediately obvious after the event with various ideas that were proposed to learn about the properties of high-density matter. Recently, we came up with yet another method that leads to interesting constraints on the properties of neutron stars, which is based on the consideration of the helium content in the ejecta. If helium is not very abundant as potentially suggested by a preliminary analysis of the kilonova spectra, the life time of the merger remnant is likely to be relatively short. This implies upper limits on the radii and the maximum mass of neutron stars. In the second part of the talk, we will discuss a new signature in stellar parameters of isolated neutron stars that indicates the presence of hyperons in the stellar core.