New building: Scanning Array. You can upgrade the scanning array in every successive TH upgrade starting at townhall 3, for a total of 5 levels. You can build spy drones in order to scan for side quests, or to spy enemy war bases.
New mechanism: Enemy war bases are no longer viewable before you launch attack.
The above has been added, it's no longer relevant.
Instead you have to send in spy drones to spy enemy war bases. The war base (along with traps) can be viewedA new update already made the above happen, it's no longer needed to add
There is a chance that espionage will show the level of buildings are wrong or misplaced. However, the higher the scanning array level and/or the more spy drones you use, the better the accuracy