Images and documents can now be organised into collections, set up by administrators through the Settings -> Collections menu item. User permissions can be set either globally (on the 'Root' collection) or on individual collections, allowing different user groups to keep their media items separated. Thank you to the University of South Wales for sponsoring this feature.
The pages shown in the explorer can now be customised using a new hook called :ref:`construct_explorer_page_queryset <construct_explorer_page_queryset>`.
The ``Document`` model can now be overridden using the new ``WAGTAILDOCS_DOCUMENT_MODEL`` setting. This works in the same way that ``WAGTAILIMAGES_IMAGE_MODEL`` works for ``Image``.
Wagtail no longer depends on the `django-compressor <http://django-compressor.readthedocs.org/>`_ library. While we highly recommend compressing and bundling the CSS and Javascript on your sites, using django-compressor places additional installation and configuration demands on the developer, so this has now been made optional.
* Snippets now support a custom ``edit_handler`` property; this can be used to implement a tabbed interface, for example. See :ref:`customising_the_tabbed_interface` (Mikalai Radchuk)
* The ``Page.path`` field is now explicitly given the "C" collation on PostgreSQL to prevent tree ordering issues when using a database created with the Slovak locale
* Logging in to the admin as a user with valid credentials but no admin access permission now displays an error message, rather than rejecting the user silently
* SASS compilation errors during Wagtail development no longer cause exit of Gulp process, instead throws error to console and continues (Thomas Winter)
* User management index view no longer assumes the presence of ``username``, ``first_name``, ``last_name`` and ``email`` fields on the user model (Eirik Krogstad)
As Wagtail no longer installs django-compressor automatically as a dependency, you may need to make changes to your site's configuration when upgrading. If your project is actively using django-compressor (that is, your site templates contain ``{% compress %}`` tags), you should ensure that your project's requirements explicitly include django-compressor, rather than indirectly relying on Wagtail to install it. If you are not actively using django-compressor on your site, you should update your settings file to remove the line ``'compressor'`` from ``INSTALLED_APPS``, and remove ``'compressor.finders.CompressorFinder'`` from ``STATICFILES_FINDERS``.
In previous releases, field validation on Page models was only applied at the form level, meaning that creating pages directly at the model level would bypass validation. For example, if ``NewsPage`` is a Page model with a required ``body`` field, then code such as:
..code-block:: python
news_page = NewsPage(title="Hello", slug='hello')
parent_page = NewsIndex.objects.get()
parent_page.add_child(instance=news_page)
would create a page that does not comply with the validation rules. This is no longer possible, as validation is now enforced at the model level on ``save()`` and ``save_revision()``; as a result, code that creates pages programmatically (such as unit tests, and import scripts) may need to be updated to ensure that it creates valid pages.
