On the Zend Framework blog they've posted the announcement about the end of life for Zend Framework v1, the first version of the popular framework.

With the release of Zend Framework 3, it's time to halt development on Zend Framework 1. As such, we hereby announce that Zend Framework 1 reaches its End of Life (EOL) three months from today, on 28 September 2016.

Between now and then, we will only provide security fixes, if any security reports are made in that time frame. Past that point, we will offer custom bug and security fixes for Zend Framework 1 on-demand only to Enterprise users of Zend Server. [...] Additionally, as of today, access to our legacy subversion server is disabled.

You can still get the latest from the package archive, use Composer for updates. There are also services from Zend that can help you update your application as well as two trainings that can help you learn what you need for the upgrade.