A few more notes for the changelog.

Since we’re nearing release, I think this about wraps up the changelog for 7.0.

Fixes jupyter-widgets#1279

Author: jasongrout

docs/source/changelog.md

@@ -14,7 +14,7 @@ Major user-visible changes in ipywidgets 7.0 include:
 - Widgets are now displayed in the output area in the classic notebook and are treated as any other output. This allows the widgets to work more naturally with other cell output. To delete a widget, clear the output from the cell. Output from functions triggered by a widget view is appended to the output area that contains the widget view. This means that printed text will be appended to the output, and calling `clear_output()` will delete the entire output, including the widget view. ([#1274](https://github.com/jupyter-widgets/ipywidgets/pull/1274), [#1353](https://github.com/jupyter-widgets/ipywidgets/pull/1353))
 - The Select widget now is a listbox instead of a dropdown, reverting back to the pre-6.0 behavior. ([#1238](https://github.com/jupyter-widgets/ipywidgets/pull/1238))
 - The Select and SelectMultiple widgets now have a `rows` attribute for the number of rows to display, consistent with the Textarea widget. The `layout.height` attribute overrides this to control the height of the widget. ([#1250](https://github.com/jupyter-widgets/ipywidgets/pull/1250))
-- Selection widgets (`Select`, `Dropdown`, etc.) now coerce their `options` argument to a tuple of `(label, value)` pairs. This makes it clearer the order in which the options will be presented. New `.value`, `.label`, and `.index` traits make it easier to observe or access the selected option.  ([#1262](https://github.com/jupyter-widgets/ipywidgets/pull/1262))
+- Selection widgets (`Select`, `Dropdown`, `ToggleButtons`, etc.) have new `.value`, `.label`, and `.index` traits to make it easier to access or change the selected option.  ([#1262](https://github.com/jupyter-widgets/ipywidgets/pull/1262), [#1513](https://github.com/jupyter-widgets/ipywidgets/pull/1513))
 - The `layout` and `style` traits can be set with a dictionary for convenience, which will automatically converted to a Layout or Style object. ([#1253](https://github.com/jupyter-widgets/ipywidgets/pull/1253))
   ```python
   IntSlider(layout={'width': '100%'}, style={'handle_color': 'lightgreen'})
@@ -30,11 +30,12 @@ Major user-visible changes in ipywidgets 7.0 include:
 - The description width is now configurable with the `.style.description_width` attribute ([#1376](https://github.com/jupyter-widgets/ipywidgets/pull/1376))
 - Selection containers (tabs, accordions) now have the convention that a `.selected_index` of `None` means no container is selected ([#1495](https://github.com/jupyter-widgets/ipywidgets/pull/1495))
 - ToggleButtons have a new `.style.button_width` attribute to set the CSS width of the buttons. Set this to `'initial'` to have buttons that individually size to the content width. ([#1257](https://github.com/jupyter-widgets/ipywidgets/pull/1257))
-
-
+- Selection container widgets (`Accordion`, `Tabs`) can have their `.selected_index` set to `None` to deselect all items. ([#1495](https://github.com/jupyter-widgets/ipywidgets/pull/1495))
+- The `IntRangeSlider` widget now has a `.readout_format` trait to control the formatting of the readout. ([#1446](https://github.com/jupyter-widgets/ipywidgets/pull/1446))
 
 Major changes developers should be aware of include:
 
+- The `jupyter-js-widgets` Javascript package has been split into `@jupyter-widgets/base` package (containing base widget classes, the DOM widget, and the associated layout and style classes), and the `@jupyter-widgets/controls` package (containing the rest of the Jupyter widgets controls). Authors of custom widgets will generally need to just depend on the `@jupyter-widgets/base` package. See the [cookie cutter](https://github.com/jupyter-widgets/widget-cookiecutter) to generate a simple example custom widget using the new packages.
 - The python `@register` decorator for widget classes no longer takes a string argument, but registers a widget class using the `_model_*` and `_view_*` traits in the class. Using the decorator as `@register('name')` is deprecated and should be changed to just `@register`. [#1228](https://github.com/jupyter-widgets/ipywidgets/pull/1228), [#1276](https://github.com/jupyter-widgets/ipywidgets/pull/1276)
 - Widgets will now need correct `_model_module` and `_view_module` Unicode traits defined.
 - Selection widgets now sync the index of the selected item, rather than the label. ([#1262](https://github.com/jupyter-widgets/ipywidgets/pull/1262))
@@ -45,6 +46,7 @@ Major changes developers should be aware of include:
 - The widget manager `clear_state` method no longer has a `commlessOnly` argument. All models in the widget manager will be closed and cleared when `clear_state` is called. ([#1354](https://github.com/jupyter-widgets/ipywidgets/pull/1354))
 - The python `ipywidget.domwidget.LabeledWidget` is now `ipywidget.widget_description.DescriptionWidget`, and there is a new `ipywidget.widget_description.DescriptionStyle` that lets the user set the CSS width of the description.
 - The model `.id` attribute has been renamed to `.model_id` to avoid conflicting with the Backbone `.id` attribute. ([#1410](https://github.com/jupyter-widgets/ipywidgets/pull/1410))
+- Custom widget managers are now responsible completely for loading widget model and view classes. Widget managers should provide an output model and view class appropriate for their environment so that the `Output` widget works. ([#1313](https://github.com/jupyter-widgets/ipywidgets/pull/1313))
 
 6.0
 ---