When you upgrade to iOS 8, most of the options are ones you’ve seen with past upgrades. But one option, asking if you’d like to upgrade to iCloud Drive, is new, and the choice you make here matters.

When you upgrade to iOS 8, you need to ensure that you choose the right iCloud Drive option to ensure that Clear for iOS continues to sync with Clear for Mac (and any older devices that may use iCloud Documents and Data). If you upgrade to iCloud Drive, you will only be able to sync with devices running iOS 8 or OS X Yosemite. As OS X Yosemite is still pre-release (and not yet available) upgrading to iCloud Drive will prevent you from syncing with Clear for Mac until both OS X Yosemite is released and you upgrade to OS X Yosemite.

Bottom line, consider holding off on the upgrade if you store documents in iCloud, or use apps that do.