Hi,
following the https://github.com/owncloud/core/wiki/Maintenance-and-Release-Schedule the ownCloud Versions reached its end-of-life with the latest release 8.0.16.
Please make sure to upgrade to a recent version like 8.1.x, 8.2.x, 9.0.x or 9.1.x in the next time to still get support and security/bug fixes.