I am using build 14986 and noticed that the GUI to Drivepool and Scanner don't work any more. The drivepool is still accessible and writable so it is functional still. However the user interface no longer works (I use it to monitor performance).
Likewise Scanner is unusable as well. I since rolled back to 14931 (which still works but Windows has other issues on that build). I don't mind upgrading to a newer beta. I have the 735 beta for Drivepool installed currently.