Update: If you upgraded to OS X 10.10 Yosemite and are having problems with iCloud Drive, please read our recent post “Problems With iCloud Drive? Here Is What You Can Do”.
Ulysses users relying on iCloud sync of various machines or with the iOS app Daedalus Touch: Please do not upgrade to iCloud Drive on your iPhone or iPad. In case you upgrade to iCloud Drive after installing iOS 8, you will no longer be able to sync your texts stored in Ulysses running on OS X Mavericks! iCloud Drive is a new storage system that syncs with the yet to be released OS X 10.10 Yosemite operating system only.
In order to prevent syncing problems, please make sure to select “Not now”, when asked if you want to upgrade to iCloud Drive during the iOS 8 installation process.
There is no workaround and no way to undo this change: Once you upgraded to iCloud Drive on any of your mobile devices, syncing will only work with devices that run iOS 8 or OS X 10.10 Yosemite.
Please also note that this applies to all apps relying on iCloud syncing. For more details, please refer to this article by Realmac’s Nik Fletcher.
PS: This post was updated on September 24, 2014 to take into account that not only users of the iOS app Daedalus Touch but all Ulysses users relying on iCloud sync are affected by this problem.