In Debian Stable you can always use backports just adding the repos to your sources. These are update version recompiled packages maintained by Debian for the Stable version.
In the case of owncloud-client package it's on 2.2.4 version (https://packages.debian.org/jessie-backports/owncloud-client)
You can understand how it works in Debian Wiki:
And how to install and use them:
I recommend them to you, I cannot live without them in my Debian Stable desktop for some packages like LibreOffice, Mozilla Firefox Firefox, etc. and of course owncloud-client.