Dev server is OPEN!
Copy the game folder to a different location. Create a file (or just copy a file and rename it) named matchingDevMode (no extension). Launch the game from the copied folder. In the laucher's options, you know the little gear picture? Click that, in the bottom-left corner, under server, select "dev". Confirm the prompt. Wait for the game to update. Launch the game. You are now in the DEV test.
A few notices i have done so far:
Fires are now sometimes exhausted, if you do aerobatic moves You can now select ammo rack type in-game, check picture:
THEY NERFED BOMBERS. NOT EVEN A 500KG BOMB NEXT TO LIGHT PILLBOX KILLS IT.
Not going to care anymore.