ownCloud does not have a feature for automatically or for manually initiating the installation of new version releases. Moving to a new release is usually achieved by installing a new newly updated Amahi package but installing the new ownCloud release manually is also possible. Reinstalling a new Amahi package is a safer practice than a manual install.
Like a lot software in the Open Source world when there is a new ownCloud version release, any Third Pary applications written by a "third party author" may not work as expected with a new release. It takes time for the third party authors to update their applications to work with the new release. Some third party applications can be "restored" from backups or re-installed from the ownCloud applications store successfully for a new version release.