You're probably thinking of this paper published by the WHO which estimates the IFR at 0.23%. Another paper by the same author states

Given that these 82 studies are predominantly from hard hit epicenters, IFR on a global level may be modestly lower. Average values of 0.15-0.20% for the whole global population and 0.03-0.04% for people <70 years old as of October 2020 are plausible.

The 0.6% IFR you mentioned is an old estimate that comes from the CDC and is actually based on a single study of 6 regions in Europe from the early stage of the epidemic. That study was published in late July.