Dash 3.0 Migration

This page outlines changes in Dash version 3.0 and cases where you may need to update an existing app to work with version 3.0.

Removed

The following were deprecated in previous versions of Dash and have now been removed in Dash 3.0.

Long Callbacks

Replace long callbacks with background callbacks.

• Instead of dash.long_callback.managers.CeleryLongCallbackManager, use dash.CeleryManager.

• Instead of dash.long_callback.managers.DiskcacheLongCallbackManager, use dash.DiskcacheManager.

• Instead of the long_callback_manager argument on the dash.Dash constructor, use background_callback_manager.

• Also, update @app.long_callback to be a standard callback with @app.callback or @dash.callback, but which sets background=True.

  For example:

  python @app.long_callback( output=Output("paragraph_id", "children"), inputs=Input("button_id", "n_clicks"), manager=long_callback_manager, )
  becomes

  python @callback( output=Output("paragraph_id", "children"), inputs=Input("button_id", "n_clicks"), background=True, manager=background_callback_manager, )

  The functionality of parameters previously available to customize app.long_callback are available on app.callback and dash.callback: interval, running, cancel, progress, progress_default, cache_args_to_ignore, and manager.

Here’s a complete app using long callbacks rewritten to use background callbacks:

dcc.LogoutButton

Replace dcc.LogoutButton with html.Button or use the Dash Enterprise Auth logout button functionality.

Dash.run_server

To run your app, replace Dash.run_server with Dash.run.

dash_core_components, dash_html_components, and dash_table Imports

Since Dash 2.0, dash_core_components, dash_html_components, and dash_table have been part of the dash package, instead of being separate packages. This changed how these packages are imported, though backwards compatibility was maintained in Dash 2.0 by including stub versions.

Dash 3.0 no longer includes the stub versions of dash_core_components, dash_html_components, and dash_table, meaning you may need to update some imports for your code to work with Dash 3.

If you have the following imports in your code, update them:

• Update import dash_core_components to from dash import dcc
• Update import dash_html_components to from dash import html
• Update import dash_table to from dash import dash_table

Default React Version

The default version of React in Dash 3.0 is React 18.3.1. In most cases, you won’t need to make any updates to your apps and they will continue to work.

If you do need to use the previous default React version (16.14.0) in your app, you can add the following:

import dash
dash._dash_renderer._set_react_version("16.14.0")

app = dash.Dash()
...

dash._dash_renderer._set_react_version("16.14.0") sets the React version to 16.14.0 and must come before the app instance is created.

Typing Support

Components in dash.html and dash.dcc now support Python typing on the component __init__. This means that static type checkers can identify issues if you pass an incorrect type when creating a component, like in the following code.

dcc.RadioItems(
    options=list(all_options.keys()),
    value=['America'], # list is not a valid type for `value`
    id='countries-radio',
),

<img>

Known issue: There is a known issue where Pyright displays errors when used with Dash 3.0. We are working on improving support for Pyright in future Dash releases. We also welcome pull requests that contribute to improving Pyright support. If you’d like to learn more about contributing to Dash, see the Contributor Guide.

Compatibility with Other Dash Libraries

If you are using any of the following libraries with Dash 3.0, you’ll need to update to the minimum version specified:

Additional Resources

• Dash 3 also introduces a new hooks feature for writing plugins. See the Writing Dash Plugins using Dash Hooks page for a guide to creating pip-installable plugins that work with Dash apps.