Assassins Creed Odyssey received a new update that has added a New Game + mode, new frames for photo mode, support for next weeks Legacy of the Blade DLC and The Lost Tales of Greece DLC that is coming down the road, and many small tweaks and balances to the game.
The New Game + mode allows you to start a new campaign of the game from the beginning but with the gear, mounts, spear upgrades, ship upgrades, abilities, drachmae, and crafting materials from a previous play through. A bonus being that you can change the character you play with, if you had done a full play through as Kassandra you can play as Alexios and vice versa.
A full list of the patch notes can be found here. Be warned that there is some major spoilage for the Lost Tales of Greece DLC that can be found in these notes.