For those wanting to change the button, or already have - pay attention.
The button is attached with a metal clip inside the case. If you just prise the old button off you leave that clip floating about, risking a short on the board.
So:
Remove the battery, duh!!
Unscrew the top and push it to one side (it's only the thick wires that make it stiff).
Look down the front of the box in front of the main board, you should see the clip. Those that haven't already removed the button will see the clip move when pressing the fire button.
Remove the clip by lifting it out with tweezers, or hold the mod upside down and jiggle the button til the clip falls out. The button will just fall out the front.
You can put it back together now, the clip isn't needed for the soft button. Just push the soft button through the hole and it'll hold itself in.
I repeat now, DON'T leave that clip floating about inside.
Why Smok omitted this info I don't know. Vape safe guys