Are they the same?
- I didn't borrow the book until today.
- Until today, I borrowed the book.
Are they the same?
Nope. But I wonder what actually the question is. If you had been borrowing the book in the past until today it is not the same as not borrowing it.
No, they are not the same
I didn't borrow the book until today.
means that I had not borrowed the book before this day, when you did.
Until today, I borrowed the book.
mean that I borrowed the book, and then I returned it -- or bought it, or something else that meant it ceased to be borrowed.