Too upgrade a weapon you take one weapon from the update 7 quests and one weapon from update 8, along with a 3rd item called "Mark of X". With 4 different marks. Based on the names they seem to keep the stats of the base item and get a bonus effect from the add-on item.
The new weapons are Gnollish War Bow, Ogrish War Axe, Staff of Shadow, and Hooked Blade (a khopesh). The scepter can only be combined with the staff. The set bonus items use 2 marks instead of a 2nd item.
I'm a little disappointed that there is not a single dex melee item between the update 7 and update 8 quests.