This was posted to the NASCAR Twitter feed on Monday afternoon:
NEWS: #NASCAR notified Sprint Cup teams today that the spoiler size for the January DIS test and the 2014 Daytona 500 event week, including the Sprint Unlimited, will be 4.5 inches tall. This is .5 inches taller than previously. NASCAR says the taller spoiler size should allow for a little more rear down force which should make the cars a little more stable.
As recently as the Charlotte test earlier this month, NASCAR officials had said they expected no changes to the Daytona rules package.