Ensign Austin Chang
He can only place 10 tripwires at a time. Placing an 11th will remove the oldest tripwire on the map.
Tripwires are no longer set off by teammates, however the base is still explosive
The Ultritium Explosive Charge (Detpack) appears in demolitionist's inventory 10 seconds after he spawns into the map and is now very small (similar to the model used in the SinglePlayer).