heretofore vs so far

heretofore and so far both are adverbs.

Word	Noun	Adjective	Verb	Adverb
heretofore	No	No	No	Yes
so far	No	No	No	Yes

As adverbs, heretofore and so far are synonyms defined as:

heretofore and so far: used in negative statement to describe a situation that has existed up to this point or up to the present time

Other synonyms of heretofore include as yet, hitherto, thus far, til now, until now, up to now, yet.

heretofore (adverb)	so far (adverb)
used in negative statement to describe a situation that has existed up to this point or up to the present time	used in negative statement to describe a situation that has existed up to this point or up to the present time
	used after a superlative
	to the degree or extent that