Thus
  networking.interfaces = [ { name = "eth0"; ipAddress = "192.168.15.1"; } ];
can now be written as
  networking.interfaces.eth0.ipAddress = "192.168.15.1";
The old notation still works though.
		
	
Thus
  networking.interfaces = [ { name = "eth0"; ipAddress = "192.168.15.1"; } ];
can now be written as
  networking.interfaces.eth0.ipAddress = "192.168.15.1";
The old notation still works though.