NLD MOD Client 188.8.131.52 is a custom-built program for tinkering with and getting more features out of DJI's drones.
At present, NLD can unlock your drone, making it possible to downgrade the firmware which means you can unlock all the features that NLD provides.
These include removing all of DJI's No Fly Zone restrictions, increasing the speed which you can fly, among many other performance upgrades!
It also allows access to all of the hidden parameters where you can make further custom changes!
[*] If you are on a firmware above .0100 you cannot downgrade due to DJI's anti-rollback. But you can send your main board in for a downgrade