Source : WordNet®

up on
     adj : being up to particular standard or level especially in being
           up to date in knowledge; "kept abreast of the latest
           developments"; "constant revision keeps the book au
           courant"; "always au fait on the latest events"; "up on
           the news" [syn: {abreast of(p)}, {au courant}, {au fait},
            {up on(p)}]