Latest at 5:00pm today: http://www.elections.gov.sg/gazette/Boundaries%20of%20altered%20polling%20districts.pdf
I misunderstood earlier that this means the Electoral Boundaries are being redrawn. Someone pointed out to me this is just a re-designation of polling districts within the existing electoral division.
Maybe it is just one of the ‘routine’ things done like the update of the Register of Electors.