Ubuntu 16.04.1 was released on 21st July 2016. According to http://www.omgubuntu.co.uk/2016/07/ubuntu-16-04-1-lts-released-upgrade

Today is also the day that users of Ubuntu 14.04 LTS (Trusty Tahr) are notified that a new Ubuntu release is ready.

I am still getting "No new release found" when trying to update my 14.04.4 desktop and a 14.04.4 server via the Software Updater and do-release-upgrade. Both have been set to notify me when new LTS versions are available. The 16.04.1 release is available from the mirror I am using. I switched to the default mirrors on the desktop but the message was the same.

Why is this the case and what can I do to fix it?