Stop freaking out that you HAVE to install Windows 8.1 Update 1 before tomorrow; Microsoft has extended the deadline to update by 30 days.
Consumers who haven't installed the Windows 8.1 update now have until June 10 to do so. Microsoft previously set the deadline as May 13, but out of concern for customer safety and enjoyment, decided it didn't need to push for this month's Patch Tuesday after all.
Why the need to update? It all comes down to safety updates. Those with devices running Windows 8.1 sans Update 1 would have no longer receive updates after the deadline passed.
Since it sounds like enough Windows 8.1 adopters have yet to one-up their OS, Microsoft is giving them an extension without any fallout. As pointed out by Mary Jo Foley at ZDNet, if you're running Windows 8, you're not subject to the update requirement. This is only for those who've hopped on the Windows 8.1 train.
Users with Automatic Update activated in Windows Update will have received the newest version of Windows 8.1 already, so there's no need to worry about updating before June 10.
Business running Windows 8.1 and Windows Server 2012 R2 have until August 12 to install their comparable upgrades. The date is actually an extension of a previous deadline Microsoft had set for companies utilizing Windows Server Update Services, Windows Intune and System Center Configuration.
When the outrage came through there wasn't enough time for businesses to upgrade their systems, Microsoft backed off and set the August date.