As most games do these days, Deus Ex: Mankind Divided had pre-order bonuses in place for early birds. Usually these things will eventually be released as DLC at a later point, but in rare cases (mostly regarding cosmetic items) these incentives remain exclusive for those who pre-ordered the game.
To be as generous as Square Enix is with Deus Ex: Mankind Divided is uncommon, though. The publisher has now released all pre-order content as a free download. The main draw is a bonus mission, but there are also skins for characters, as well as some new weapons (amongst other things). A minor patch has also been released for PC which fixes the following things:
• Fixes an issue where the weapon inventory bar would not be saved online.
• Fixes some crash issues occurring with specific save files from users.
• Quit Game option is now aligned with the other menu options.