'up on' definitions:

Definition of 'up on'

From: WordNet
adjective
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(p), au courant, au fait, up on(p)]

Synonyms of 'up on'

From: Moby Thesaurus