How does the app sync my data?
The app use iCloud in a specific way: each one of your devices writes what it has done in a specific folder (called Container) in iCloud (that is on Apple’s servers). This container is tied to your Apple ID and is specific for each app. Each of your devices can see this container, and thus each one can see what the others have done. After some clever integration, each device decide what to do on its side so every one will have the same state at the end.
This has several advantages, but the main one is that the data on iCloud is disposable: each of your devices is able to regenerate its corresponding missing data.
iCloud sync has stopped and you use iOS 7 and iOS 8.
With iOS 8, Apple has introduced iCloud Drive. When you start a device for the first time with iOS 8, the app ask you if you want to convert your iCloud account to use iCloud Drive. It also warns you that if you do that, iCloud sync will stop for iOS 7 devices (which don’t know how to talk to iCloud Drive). If ever you activated iCloud Drive, you can’t use iCloud anymore to sync data between your iOS 7 and iOS 8+ devices. This is completely out of reach of developers, so we can’t do anything about it.
Dropbox as an alternative sync service is planned, so your iOS 7 devices may sync again in a near future.
How to fix iCloud sync
if iCloud sync as stopped, for a reason or another, you can try to reset your iCloud container for Chord!:
- Backup your data (it never hurts!).
- Switch off synchronization in the settings of Chord! on each of your devices.
- Close the app on each of your devices by double tapping the Home button and sliding Chord! thumbnail toward the top of your screen.
Now that Chord! isn’t runing, with only one of your devices, go in the Settings of iOS, General, Usage, iCloud: Manage storage, then select “Chord!”, then “Edit”, then “Delete everything”. This will delete the app’s container in your iCloud account, and this information will propagate to each of your devices, so wait about 5 or 10 minutes.
You can launch Chord! and reactivate iCloud sync on each of your devices. Each one will rebuild its bits in the container and sync should start again. It can take a few minutes the first time, so please be patient.