I think they said 9 hours originally so add 7 subtract 2 for an announcement then figure another 15 for emergency patches to fix the patch.
actually the servers came up... and then got taken back down already a few hours ago (and early). so we are in the patch to fix the patch.
A Sarnak incursion was discovered, extending today's maintenance another 2 hours. Thanks for your patience! That was posted it says 51 minuets ago on twitter so looks like it will be up shortly.