Good morning, jiaruchan.
(1) I am sure that some persons will soon give you a better answer than mine.
(2) I do NOT think they are the same -- certainly not in every case.
(3) For example, I regularly visit a news website.
(a) It often says: the news was updated five minutes ago.
(i) That the latest news has just been posted.
(ii) In other words, to update = to revise; to change; to add.
(4) Up-to-date means exactly that: something is up (reaches) today's date.
FATHER: For your 18th birthday, I am going to give you a 1985 Ford automobile.
SON: Aw, Dad, everyone will laugh at me. I need an up-to-date car.
(P. S. This is a terrible example, but I think you get the idea.)
(i) Maybe another word for "up-to-date" is something like "modern" or "contemporary."
Have a nice day!
- For Teachers