I'm using the package siunitx for unit-typesetting.
In particular I wanted this expression:
\SI[per=frac,fraction=nice]{2}{\celsius\per\kilo\metre}
unfortunately I get many errors like:
siunitx error: version-1-option
version 1 option 'per' detected
Similarly for fraction
Without the option part it works:
\SI{2}{\celsius\per\kilo\metre}
I'm thinking that is because I'm not using latin but utf8 (inputenc) encoding, but not sure?! Any advice?

texdoc siunitxfrom a command prompt/terminal, – Torbjørn T. Sep 03 '16 at 22:53range-phrase=--for an en dash. Probably\dotsinstead of--for dots. – Torbjørn T. Sep 03 '16 at 22:55nicereferred to thexfracpackage and not to thenicefracpackage and its\nicefraccommand? (Of coursexfracallows for customization so it offers more flexibility…) – cgnieder Sep 04 '16 at 11:41siunitx? Let's say I want to type1/2 kg. Can I combine\nicefracor\sfracwithsiunitx? – Gagik Apr 20 '22 at 08:27