Fans are hoping for some killer Skyrim DLC after the so-so "House Armor" release Hearthfire, and newly discovered code in the PC game's latest update hints at just that, in Dragonborn (via OXM). The rumored DLC pack adds a number of new elements to the game, based on the update files, most notably a new feature that allows players to use dragons as mounts. YES.
There are also indications in the update files that the upcoming quest content returns to the land of Morrowind, last seen in The Elder Scrolls 3. There are apparently quest markers for familiar locations from the distant land, including Solstheim, Telvanni, Castle Karstaag, Raven Rock, and Miraak Temple. It also appears that some new armor types are being added to the game: Bonemold, Chitin, Nordin, and Stalhrim.
It's all unconfirmed rumor until Bethesda goes on record with confirmation, but seeing as this info all comes from the latest PC game update, it's probably okay to get your hopes up. At least a little bit.