<p>if I decide to drop a class and receive a W, do I have to notify each school "personally via-email or mail".. or will the TAU (transfer admission update) be enough?</p>
<p>I would do both, update the TAU and let all the schools know individually; since it is past Jan 31st they might not look at your TAU again. I know UCSD wants you to use a form on MyApplication and Berkeley wants snail mail, so it’d be best to check each campus you applied to and see what they want.</p>