updated 03:10 pm EDT, Tue April 8, 2014
Build-promoted 'Start' menu changes not implemented yet
Microsoft has started making the latest major update to Windows 8.1 available to end users. The mandatory update for Windows 8.1 users comes in a series of patches, and requires that the user have a fully-patched existing 8.1 system before the update commences. Failure to properly install the patch has dire consequences, according to Microsoft -- engineers claim that "failure to install this Update will prevent Windows Update from patching your system with any future updates starting with Updates released in May 2014."
In a Microsoft engineering blog, Michael Hildebrand notes that the update "is actually a series of packages that install collectively and provide UI and functionality improvements" and includes "a big IE feature-add as well as some heavy-lifting internal changes to Windows boot structures and memory/resource awareness and management" in addition to changes to the user interface of Windows 8.1.
Electronista tested the install on a series of computers, with between 5-7 patches required before the full 887mb update was installed. All of the machines had last been updated less than two weeks prior. After all smaller patches are installed, we had to run the software check one more time, and manually select the full 8.1 patch for it to install -- as it was not tagged as "important," despite being called so by Microsoft. The entire process took nearly an hour and a half on a Haswell Core i5 processor-equipped machine, and an hour and 17 minutes on a Core i7 device.