` and `
` elements with attributes (Matt Westcott)
* Added limit image upload size by number of pixels (Thomas Elliott)
* Added `manage.py wagtail_update_index` alias to avoid clashes with `update_index` commands from other packages (Matt Westcott)
* Renamed `target_model` argument on `PageChooserBlock` to `page_type` (Loic Teixeira)
* `edit_handler` and `panels` can now be defined on a `ModelAdmin` definition (Thomas Kremmel)
* Add Learn Wagtail to third-party tutorials in documentation (Matt Westcott)
* Add a Django setting `TAG_LIMIT` to limit number of tags that can be added to any taggit model (Mani)
* Added instructions on how to generate urls for `ModelAdmin` to documentation (LB (Ben Johnston), Andy Babic)
* Added option to specify a fallback URL on `{% pageurl %}` (Arthur Holzner)
* Add support for more rich text formats, disabled by default: `blockquote`, `superscript`, `subscript`, `strikethrough`, `code` (Md Arifin Ibne Matin)
* Added `max_count_per_parent` option on page models to limit the number of pages of a given type that can be created under one parent page (Wesley van Lee)
* `StreamField` field blocks now accept a `validators` argument (Tom Usher)
* Added edit / delete buttons to snippet index and “don’t delete” option to confirmation screen, for consistency with pages (Kevin Howbrook)
* Added name attributes to all built-in page action menu items (LB (Ben Johnston))
* Added validation on the filter string to the Jinja2 image template tag (Jonny Scholes)
* Changed the pages reordering UI toggle to make it easier to find (Katie Locke, Thibaud Colas)
* Added support for rich text link rewrite handlers for `external` and `email` links (Md Arifin Ibne Matin)
* Clarify installation instructions in documentation, especially regarding virtual environments. (Naomi Morduch Toubman)
### Bug fixes
* Set `SERVER_PORT` to 443 in `Page.dummy_request()` for HTTPS sites (Sergey Fedoseev)
* Include port number in `Host` header of `Page.dummy_request()` (Sergey Fedoseev)
* Validation error messages in `InlinePanel` no longer count towards `max_num` when disabling the ‘add’ button (Todd Dembrey, Thibaud Colas)
* Rich text to contentstate conversion now ignores stray closing tags (frmdstryr)
* Escape backslashes in `postgres_search` queries (Hammy Goonan)
* Parent page link in page chooser search results no longer navigates away (Asanka Lihiniyagoda, Sævar Öfjörð Magnússon)
* `routablepageurl` tag now correctly omits domain part when multiple sites exist at the same root (Gassan Gousseinov)
* Added missing collection column specifier on document listing template (Sergey Fedoseev)
* Page Copy will now also copy ParentalManyToMany field relations (LB (Ben Johnston))
* Admin HTML header now includes correct language code (Matt Westcott)
* Unclear error message when saving image after focal point edit (Hugo van den Berg)
* Increase max length on `Embed.thumbnail_url` to 255 characters (Kevin Howbrook)
* `send_mail` now correctly uses the `html_message` kwarg for HTML messages (Tiago Requeijo)
* Page copying no longer allowed if page model has reached its `max_count` (Andy Babic)
* Don’t show page type on page chooser button when multiple types are allowed (Thijs Kramer)
* Make sure page chooser search results correspond to the latest search by canceling previous requests (Esper Kuijs)
* Inform user when moving a page from one parent to another where there is an already existing page with the same slug (Casper Timmers)
* User add/edit forms now support form widgets with JS/CSS media (Damian Grinwis)
* Rich text processing now preserves non-breaking spaces instead of converting them to normal spaces (Wesley van Lee)
* Prevent autocomplete dropdowns from appearing over date choosers on Chrome (Kevin Howbrook)
* Prevent crash when logging HTTP errors on Cloudflare cache purging (Kevin Howbrook)
* Prevent rich text editor crash when filtering copy-pasted content and the last block is to be removed, e.g. unsupported image (Thibaud Colas)
* Removing rich text links / documents now also works when the text selection is backwards (Thibaud Colas)
* Prevent the rich text editor from crashing when copy-paste filtering removes all of its content (Thibaud Colas)
* Page chooser now respects custom `get_admin_display_title` methods on parent page and breadcrumb (Haydn Greatnews)
* Added consistent whitespace around sortable table headings (Matt Westcott)
* Moved locale names for Chinese (Simplified) and Chinese (Traditional) to `zh_Hans` and `zh_Hant` (Matt Westcott)
## Upgrade considerations
### `EditHandler.bind_to_model` and `EditHandler.bind_to_instance` deprecated
The internal `EditHandler` methods `bind_to_model` and `bind_to_instance` have been deprecated, in favor of a new combined `bind_to` method which accepts `model`, `instance`, `request` and `form` as optional keyword arguments. Any user code which calls `EditHandler.bind_to_model(model)` should be updated to use `EditHandler.bind_to(model=model)` instead; any user code which calls `EditHandler.bind_to_instance(instance, request, form)` should be updated to use `EditHandler.bind_to(instance=instance, request=request, form=form)`.
### Changes to admin pagination helpers
Several changes have been made to pagination handling within the Wagtail admin; these are internal API changes, but may affect applications and third-party packages that add new paginated object listings, including chooser modals, to the admin. The `paginate` function in `wagtail.utils.pagination` has been deprecated in favor of the `django.core.paginator.Paginator.get_page` method introduced in Django 2.0 - a call such as:
```python
from wagtail.utils.pagination import paginate
paginator, page = paginate(request, object_list, per_page=25)
```
should be replaced with:
```python
from django.core.paginator import Paginator
paginator = Paginator(object_list, per_page=25)
page = paginator.get_page(request.GET.get('p'))
```
Additionally, the `is_ajax` flag on the template `wagtailadmin/shared/pagination_nav.html` has been deprecated in favour of a new template `wagtailadmin/shared/ajax_pagination_nav.html`:
```html+django
{% include "wagtailadmin/shared/pagination_nav.html" with items=page_obj is_ajax=1 %}
```
should become:
```html+django
{% include "wagtailadmin/shared/ajax_pagination_nav.html" with items=page_obj %}
```
### New rich text formats
Wagtail now has built-in support for new rich text formats, disabled by default:
* `blockquote`, using the `blockquote` Draft.js block type, saved as a `
` tag. * `superscript`, using the `SUPERSCRIPT` Draft.js inline style, saved as a `` tag. * `subscript`, using the `SUBSCRIPT` Draft.js inline style, saved as a `` tag. * `strikethrough`, using the `STRIKETHROUGH` Draft.js inline style, saved as a `` tag. * `code`, using the `CODE` Draft.js inline style, saved as a `` tag. Projects already using those exact Draft.js type and HTML tag combinations can safely replace their feature definitions with the new built-ins. Projects that use the same feature identifier can keep their existing feature definitions as overrides. Finally, if the Draft.js types / HTML tags are used but with a different combination, do not enable the new feature definitions to avoid conflicts in storage or editor behavior. ### `register_link_type` and `register_embed_type` methods for rich text tag rewriting have changed The `FeatureRegistry.register_link_type` and `FeatureRegistry.register_embed_type` methods, which define how links and embedded media in rich text are converted to HTML, now accept a handler class. Previously, they were passed an identifier string and a rewrite function. For details of updating your code to the new convention, see [Rewrite handlers](../extending/rich_text_internals.md#rich-text-rewrite-handlers). ### Chinese language locales changed to `zh_Hans` and `zh_Hant` The translations for Chinese (Simplified) and Chinese (Traditional) are now available under the locale names `zh_Hans` and `zh_Hant` respectively, rather than `zh_CN` and `zh_TW`. Projects that currently use the old names for the `LANGUAGE_CODE` setting may need to update the settings file to use the new names.