Time Traveler is an achievement/trophy in Deus Ex: Mankind Divided. It is awarded for bringing Václav Koller the neuroplasticity calibrator before he asks for it in the mission Getting in Top Shape Again.
This achievement is mutually exclusive to getting the Honor Holds Us All Together achievement. As such, one can either do different playthroughs to get both or revert to an earlier save.
Jensen must travel to Otar Botkoveli's casino, and steal the calibrator from his office before doing Getting in Top Shape Again. As the casino will be restricted with no option of talking to Otar, one must sneak in or go in shooting. The calibrator will be in Otar's safe (4863).
Once retrieved, go visit Koller in The Time Machine. Koller will eventually mention the calibrator to which Jensen will respond he already has it, netting the achievement.
- Despite retrieving the calibrator before talking to Koller, he will state he cannot install it yet as he wants to do some research first to make sure everything goes smoothly.