I saw a new updated payment schedule and for the life of me I can't find it now.
BUT I do remember that it stated since the payments were going 4 days earlier than expected thereby pushing up all other payment schedules.
So....if you're waiting for a paper check, just look at the IRS website payment schedule and if they have for instance a payment schedule for SS# ending in 17, your check should be mailed out May 16th.
HOWEVER, I've been reading on the IRS website that they have a NEW system this year to where they can send out payments everyday instead of once a week. Meaning you could possibly get your payments sooner than expected.
Here's hoping!