Microsoft's (Nasdaq: MSFT) Windows 8.1 Update is a necessary install. The company even said so itself.

With it's latest blog post, Microsoft said:

It is a required update to keep your Windows 8.1 device current

-- Failure to install this Update will prevent Windows Update from patching your system with any future updates starting with Updates released in May 2014 (get busy!)

To examine what the update has in store, click here.

Shares of Microsoft are up in early trading Tuesday.