Basically the title. Do update letters really do anything after April 30th? I've already sent mine before, but I'm continuing volunteering up until the end of May and if I were to update schools about how that's been going/how many hours I've completed, does it actually make a difference at that point? I know one of the schools that I'm waitlisted at has a ranked waitlist and was told that any updates won't make any changes to their rankings, so it got me thinking for other schools.