This is one of those updates that should have happened long ago. Instagram Stories will now accept any content regardless whether it was created in the last 24hrs or not.
This was a limitation that caused a number of people (including a number of celebs) to find creative ways to bypass.
People would either re-save, take screenshots of content, or change the metadata in images and vids to fool Instagram.
Instagram have realised their self-imposed limitation was not working and have thrown in the towel.
This is a wise move by Instagram and a welcome one by users.