In a few more hours, Apple will release iOS 8 to the public. It may take a while before you get the update notification (Settings -> General -> Software Update) but in all probability, you will be upgrading to the latest iOS 8 today.
Out of all the interesting new features (like Continuity, Handoff, customizable keypads, Health app etc.), iCloud Drive is an option that might cause a problem if you enable it already. Here’s more on this and how to avoid any problems when you upgrade to iOS 8.
Don't Enable iCloud Drive
When you setup iOS 8 on your iPhone/iPad, you will see this screen.
iCloud Drive is a new feature specific to iOS 8 and OS X Yosemite. When setting up iOS 8 on your device, select Not Now. (more on “why?” later).
You can obviously enable iCloud Drive later from Settings -> iCloud -> iCloud Drive switch/options. For the moment though, do not enable iCloud Drive.
Why Should You Disable iCloud Drive When Upgrading to iOS 8?
To understand why, we must first understand “what.”
iCloud Drive is a new feature that lets you place app-related documents in a drive similar to Google Drive or Dropbox. You can access these files from your Mac or any other iCloud-connected device. The only issue is that iCloud Drive works only for iOS 8 and OS X Yosemite. As you know, OS X Yosemite is still in beta stages.
So, what can happen is, your app-related docs (and data) will get into iCloud Drive but you won't be able to access them on the Mac (or any device that is not running iOS 8 or OS X Yosemite).
The worst case scenario is this: you have an app that syncs data (photos, videos, messages, files) between your iOS devices and now (if you had enabled iCloud Drive) you can’t access those files/sync.
iCloud Drive is not a separate feature to iCloud docs. When you enable iCloud Drive, all the files and data stored in your iCloud account server will be transferred to iCloud Drive’s servers. There is nothing to worry here because as a user, there is nothing changing for you in terms of the experience.
But just for now, do not enabled iCloud Drive.