Can't disable automatic app update on ipad ios 8.1.3

I just updated an Ipad2 to ios 8.1.3. This ipad is wifi only. I want to disable automatic app updates (I've been burned before with this) but the ipad won't let me toggle the update button from green to white. I can move it to white, but it just slides itself back to green! I've tried this with the ipad connected to wifi and not connected. Any help would be appreciated!