Max altitude setting does not have a slider. It looks like we can't disable it. So there is no way to fly this bird above 500 meters by the looks of it. Perhaps the max altitude is only applied in GPS mode though, not sure.
You are right. In the latest version of the App the slider has disappeared. So right now the max altitude is limited to 500m.
This is a scary thought.
We are at the mercy of DJI with each subsequent firmware updates.
First DJI removed the Sat count and now we only have Bars.
Now the 500m limit.