After you wake up in Prague, your Augs start malfunctioning. To fix them, you need to find Vaclav Kollar, who is being accosted by Dvali thugs. Use this Deus Ex Mankind Divided guide to learn how to track down Vaclav Kollar.
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Deus Ex Mankind Divided - How to Find Vaclav Kollar
Once you get the call from Kollar asking for help, follow the waypoint until you come to a gate door guarded by a man who says the area is being used. You can either knock the guy out and go through or complete The Golden Ticket side mission to get through the checkpoint nearby. Once through, make your way to the Time Machine bookstore, where a large group of thugs are laying siege to the place.
From here, you can either proceed by systematically taking all the enemies out or through stealth. Note that you don't need to clear the area to complete the mission. You only have to get to Kollar. The best way to start is by climbing the ladder by the archway just before the bookstore. If you've got a sniper rifle, you can start sniping on the arch at the enemies outside with a very slim chance of being caught. There are many enemies in the building itself, however, and sniping wont work so well in those close quarters.
From the arch, you can drop down and head left to a dead end and climb a ladder you find there. Once you do, you can move along the window ledges until you get to an open window. Neutralize the guards there and follow the beacon to Koller's office. Koller will call you and tell you how to access his dungeon, a red book which reveals an elevator. If you don't see it, the waypoint will mark it outright. Go down the elevator to find Koller, get your Augs fixed, and gain access to Experimental Augs. Once you're done, you can exit through the back of the dungeon and back up to the street via a manhole.