Considering they only ever announce maintainence a few hours before and not days in advance, I'm gonna say they meant Tuesday. Only the Season updates are announced a few days in advance and sadly this ain't it.
4 hours as opposed to two? extended maintenance? Season 4, mebbe?
Season 4 isn't ready for Tribble as yet - nevermind the Holodeck server. That said they could be upgrading their hardware base in preperation for Season 4 going on to the Live server in a month or two.