You can only run one instance of & kmail; at once. We also recommend to stick to a certain version and not switch back and forth between different versions. Downgrading to an older version will probably cause problems, & eg; because the index file formats might have changed. Upgrading should never be a problem.
Naenkrat lahko poganjaš le eno verzijo & kPošte;. Svetujemo ti, da verzij ne menjavaš, saj "povratno nadgrajevanje" (angl. downgrading ") lahko povzroči resne probleme, & npr; zaradi spremembe oblike indeksnih datotek... Nadgrajevanje naj ne bi bil problem.