Released on December 14, 2021, Assassin’s Creed Odyssey Update 1.5.6 introduced the free "Crossover Stories" content, including a new questline on Corfu Island. The patch adds fast travel to ports and, on consoles, requires significant download sizes ranging from approximately 13.2 GB to 20.7 GB. For complete details, see the Attack of the Fanboy patch notes
PC (Ubisoft Connect / Steam):