UESPWiki:News/Possible Expansion Packs?
 Possible Expansion Packs?
On August 17th, ZeniMax Media Inc. applied for registration on the trademarks "Shivering Isles" and "Knights of the Nine". Bethesda Softworks has neither confirmed nor denied that they are developing expansion packs for Oblivion, so it could be possible that they are developing expansion packs by these names. Alternatively, these could be the names of two unrelated projects. Let the speculation begin! (Search for these US trademarks here.)
A member of the official forums has argued that the wording of these two trademarks indicates that these titles will instead be Elder Scrolls Travels games.  In brief, the four core TES games and their expansion packs are all registered under "Computer game programs", while Shadowkey and Oblivion Mobile as well as these two unused names all use the wider description "Computer game programs; computer game programs offered via handheld computers, wireless telephones and wireless devices."
Knights of the Nine is now known as an upcoming official mod/plug-in, albeit one that will be released as a boxed set including all the previous official plug-ins, meaning that it can be viewed as an "expansion" of sorts. Some speculate that "Shivering Isles" will take place in Lore:Summerset Isle.