Ahhh...I completely forgot about the servers. Being naive I would expect them to have two teams working on it simultaneously.

Here is also some food for thought. I've done very very limited coding (I got a C in java many years ago and decided to switch majors --about 10 years ago? idk anyways besides the point). Why wouldn't they have all the coding pre-prepared and simply "copy and paste" it over and reboot everything? Obviously it's not that simple but I guess it would make more sense to me that way.

Perhaps a live test server where they could have all the "down time" and patching nonsense and then for the real game just copy stuff over.

I guess it comes down to man power and them not having enough of it?