# Wagtail 4.0 release notes - IN DEVELOPMENT

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## What's new

### Other features

 * Add clarity to confirmation when being asked to convert an external link to an internal one (Thijs Kramer)
 * Convert various pages in the documentation to Markdown (Khanh Hoang, Vu Pham, Daniel Kirkham, LB (Ben) Johnston)
 * Add `base_url_path` to `ModelAdmin` so that the default URL structure of app_label/model_name can be overridden (Vu Pham, Khanh Hoang)
 * Add `full_url` to the API output of `ImageRenditionField` (Paarth Agarwal)
 * Use `InlinePanel`'s label when available for field comparison label (Sandil Ranasinghe)
 * Drop support for Safari 13 by removing left/right positioning in favour of CSS logical properties (Thibaud Colas)
 * Use `FormData` instead of jQuery's `form.serialize` when editing documents or images just added so that additional fields can be better supported (Stefan Hammer)
 * Add informational Codecov status checks for GitHub CI pipelines (Tom Hu)
 * Make it possible to reuse and customise Wagtail’s fonts with CSS variables (LB (Ben) Johnston)

### Bug fixes

 * Fix issue where `ModelAdmin` index listings with export list enabled would show buttons with an incorrect layout (Josh Woodcock)
 * Fix typo in `ResumeWorkflowActionFormatter` message (Stefan Hammer)
 * Throw a meaningful error when saving an image to an unrecognised image format (Christian Franke)
 * Remove extra padding for headers with breadcrumbs on mobile viewport (Steven Steinwand)
 * Replace `PageRevision` with generic `Revision` model (Sage Abdullah)
 * Ensure the upgrade notification request for the latest release, which can be disabled via the `WAGTAIL_ENABLE_UPDATE_CHECK` sends the referrer origin with `strict-origin-when-cross-origin` (Karl Hobley)
 * Ensure radio buttons / checkboxes display vertically under Django 4.0 (Matt Westcott)


## Upgrade considerations

### `base_url_path` keyword argument added to AdminURLHelper

The `wagtail.contrib.modeladmin.helpers.AdminURLHelper` class now accepts a `base_url_path` keyword argument on its constructor. Custom subclasses of this class should be updated to accept this keyword argument.

### Dropped support for Safari 13

Safari 13 will no longer be officially supported as of this release, this deviates the current support for the last 3 version of Safari by a few months and was required to add better support for RTL languages.

### `PageRevision` replaced with `Revision`

The `PageRevision` model has been replaced with a generic `Revision` model. If you use the `PageRevision` model in your code, make sure that:

 * Creation of `PageRevision` objects should be updated to create `Revision` objects using the page's `id` as the `object_id`, the default `Page` model's content type as the `base_content_type`, and the page's specific content type as the `content_type`.
 * Queries that use the `PageRevision.objects` manager should be updated to use the `Revision.page_revisions` manager.
 * Queries for `Page` objects that use `PageRevision.page_id` should be updated to cast the `Revision.object_id` to an integer before using it in the query.