Yomu keeps your books, annotations, folders, tags and reading progress stored securely in Apple’s iCloud. Every time you change something on one device, it’s synced to all your other devices. Always have the latest version, when you start reading on your iPad or Mac and continue on your iPhone on the go.

Yomu saves documents and data in Apple’s iCloud. Please note that you need to be signed in on your device with the same Apple ID on all platforms.

The Cloud Library is only available in Yomu Pro and requires a personal iCloud account. Storage limits apply and depend on your corresponding plan.

Apple’s CloudKit framework is used to save all metadata and files. Like with Photos, Books or other apps, all data is stored in a private database in your personal iCloud account. Only devices linked to your account have access, it is not possible for users or developers to directly view or download stored documents and data.

Yomu is intended as an ebook reader (client), not a document management system or server. It is recommended to still keep your original books on your computer, some kind of cloud storage provider (Dropbox, Google Drive, Nextcloud) or using a dedicated ebook management software (Calibre, COPS).

The size for individual documents is limited to a maximum of 100MB per file. The Cloud Library is optimized for up to 500 books or a total size of 600MB. Everything above these limits can lead to memory or storage issues and synchronization no longer works reliably.

When enabling the Cloud Library, your current library will be saved to iCloud and synced to your other devices. You will need to be signed in on your device with your Apple ID and iCloud Drive must be available.

By default, synchronisation is disabled, you will need to enable it individually for each of your devices. Open the left sidebar in Yomu and tap on Cloud or go to Settings > Cloud in order to start the setup.

When you enable this feature, your current local library will be saved to iCloud. Imported books will not be merged with already existing ones. This means that if you have the “same” book on two devices, it will show up twice, since each import is assigned a different unique identifier when first syncing.

Important:
Do not interrupt this process.

When iCloud synchronisation is enabled, changes to documents, annotations, folders and tags as well as your current reading state (chapter/page) are automatically synced to all enabled devices.

Devices are notified of changes by silent push notifications. This requires Background App Refresh to be enabled for Yomu in Settings > General > Background App Refresh. As a fallback or if you do not want to enable automatic refreshing, a periodic sync fetches changes in regular intervals.

In most cases, synchronisation happens automatically and within minutes. But since notifications are not guaranteed to be always delivered or can be turned off, you might not see updates until the next periodic sync. In case changes are not transferred automatically, you can also use «pull-to-refresh» for a manual synchronisation.

In case you disable iCloud synchronisation, documents and data will no longer be synced for that particular device. You can opt out for each of your previously enabled devices individually.

Open the left sidebar and go to Settings > Cloud. Switching the Cloud Library to off will show the cloud setup, where you can disable synchronisation for the current device.

Cloud synchronisation will be disabled for the corresponding device. If you enable it again later, this device will sync up to the latest state stored on iCloud.

When disabling iCloud synchronisation on a device, your library is still stored on iCloud. In case you want to completely remove all stored data after you have disabled all your devices, go to Settings > iCloud > Storage > Manage > Yomu and delete all documents and data.

Important:
Please note that if you choose to delete all documents and data from the settings, your stored library can not be recovered and will no longer be available to any device linked to your account.

Please note that there is currently an issue where iCloud sync might not work anymore on older operating systems.

Apple’s iCloud service deprecated an operation and their servers now suddenly started to return an error. For older iOS/macOS system versions, requests are somehow rejected by iCloud servers, which is a non-recoverable error. On newer operating systems, it’s just a “bad request” that gets ignored by the app.

Yomu v3.7.0 should fix this iCloud bug. Otherwise you would need to upgrade your iPhone/iPad/Mac operating system to the latest version, which should solve the problem as well.

Apple’s iCloud service is used to store and sync your library. It’s a secure and (in most cases) reliable service, but problems can occur. It is unfortunately not possible for developers to find out why something does not work for certain users.

Make sure iCloud is setup and working:

• Verify you are signed in:
  Settings > Apple ID
• Verify iCloud and iCloud Drive is enabled:
  Settings > Apple ID > iCloud
  iCloud > iCloud Drive > Apps > Yomu
• Verify network connection is available (no flight mode, vpn etc.):
  Settings > Network

If iCloud can’t be enabled or your library is not synced:

• Try again later
  → Maybe iCloud is temporarily unavailable
• Relaunch the app
  → This should refresh iCloud synchronization
• Restart your device
  → This should relaunch iCloud system services
• Uninstall/reinstall the app
  → This should reinitialise iCloud zones and records
• Logout/login from your Apple iCloud account (at your own risk):
  → This should reconnect your device and iCloud account

All books, folders, annotations and tags of your library are stored in a private database of your personal iCloud account. But reading state (chapter/page) uses a different service (iCloud Key-Value Store). If your library is synced but current reading progress not updated, it could be a different problem.

Reading position should be synced either when you close a book or when the app goes to background. It gets updated when the app becomes active and periodically while running. Unfortunately, iCloud state sync is sometimes rather slow (can take some minutes) or is unreliable for some devices.

When reading progress is not updated:

• Wait some time between switching devices
• Quit and restart the app again a bit later
• Close all apps and restart your device

If iCloud storage or sync still does not work it’s most likely a problem with your device or account. iCloud is a service provided by Apple, please refer to their documentation or contact Apple support for any iCloud related issues.

Apple iCloud Support:
https://support.apple.com/icloud

Yomu uses Apple’s iCloud service to store and sync your library. It’s a secure and (in most cases) reliable service, but problems can occur during synchronisation.

For general problems with iCloud, please refer to Apple’s official support:
https://support.apple.com/icloud

Below you find a list of the most common iCloud errors. Most problems are recoverable (e.g. no network), but some of them are fatal and require to re-enable synchronisation.

Recoverable Problems

Fatal Problems

In case of a fatal error, it is generally best to disable iCloud synchronisation for that particular device and enable it again after you fixed the problem. Since your data is stored in your local library and on Apple’s iCloud, the affected device should sync up again without any lost information.