Use APCu only if available in version 4.0.6 and higher. If you install an older version, you will see a APCu below version 4.0.6 is installed, for stability and performance reasons we recommend to update to a newer APCu version warning on your ownCloud admin page.

SMB external storage now based on php5-libsmbclient , which must be downloaded from the ownCloud software repositories (installation instructions).

Download from link feature has been removed.

The .htaccess and index.html files in the data/ directory are now updated after every update. If you make any modifications to these files they will be lost after updates.

The SabreDAV browser at /remote.php/webdav has been removed.

Using ownCloud without a trusted_domain configuration will not work anymore.

The logging format for failed logins has changed and considers now the proxy configuration in config.php .

A default set of security and privacy HTTP headers have been added to the ownCloud .htaccess file, and ownCloud administrators may now customize which headers are sent.

More strict SSL certificate checking improves security but can result in cURL error 60: SSL certificate problem: unable to get local issuer certificate errors with certain broken PHP versions. Please verify your SSL setup, update your PHP or contact your vendor if you receive these errors.

The persistent file-based cache (e.g. used by LDAP integration) has been dropped and replaced with a memory-only cache, which must be explicitly configured. See configuration/user/user_auth_ldap. Memory cache configuration for the ownCloud server is no longer automatic, requiring installation of your desired cache backend and configuration in config.php (see configuration/server/caching_configuration.)

The OC_User_HTTP backend has been removed. Administrators are encouraged to use the user_webdavauth application instead.

ownCloud ships now with its own root certificate bundle derived from Mozilla’s root certificates file. The system root certificate bundle will not be used anymore for most requests.

When you upgrade from ownCloud 8.0, with encryption enabled, to 8.1, you must enable the new encryption backend and migrate your encryption keys.

Encryption can no longer be disabled in ownCloud 8.1. It is planned to re-add this feature to the command line client for a future release.

It is not recommended to upgrade encryption-enabled systems from ownCloud Server 8.0 to version 8.1.0 as there is a chance the migration will break. We recommend migrating to the first bugfix release, ownCloud Server 8.1.1.

Due to various technical issues, by default desktop sync clients older than 1.7 are not allowed to connect and sync with the ownCloud server. This is configurable via the minimum.supported.desktop.version switch in config.php .

Previews are now generated at a maximum size of 2048 x 2048 pixels. This is configurable via the preview_max_x and preview_max_y switches in config.php .

The ownCloud 8 server is not supported on any version of Windows.

The 8.1.0 release has a minor bug which makes application updates fail at first try. Reload the apps page and try again, and the update will succeed.

The forcessl option within the config.php and the Enforce SSL option within the Admin-Backend was removed. This now needs to be configured like described in Hardening and Security Guidance.

WebDAV file locking was removed in ownCloud 8.1 which causes Finder on macOS to mount WebDAV read-only.