Hello,
I tried to update my notifications from Alert to Alert+email (default on my profile). I clicked the square for all, and clicked "USE DEFAULT PREFERENCE". For topics, it works (even if I need to go page by page, not all at once - by the way, since I have many pages, is there a solution to change for all pages?). But for boards, it does not work and I need to go to each board and click "Notify alert+email".