When VuFind 2.0 went into development, the Zend Framework community was in the process of developing their own 2.0 version. This led to an unfortunate situation: the first iteration of VuFind 2.0 development had to use Zend Framework 1, even though a new and different version of the software was on its way. This is why the 2.0alpha release uses ZF1 but subsequent versions are built for ZF2.

For more information, see the general Zend Framework 2.0 page.