This time it’s the end for “iCloud Documents and Data”, iCloud’s former cloud document synchronization service: Apple has confirmed that it has just been replaced by iCloud Drive in this help sheet update for the occasion (only in English for the moment). The users concerned are those who remained under OS X Yosemite (10.10), iOS 8 or Windows 7 for PCs. All other users on newer systems can already use iCloud Drive.
While data transfer between iCloud Documents and Data and iCloud Drive is automatic, Apple still requires users to enable iCloud Drive to view their files (in iCloud settings). At least for those using the old service, of course. The file storage volume obviously does not change from cloud to cloud.
Apple warned of iCloud Documents and Data retirement one year ago. iCloud Drive was launched in 2014, during the then WWDC.