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Upgrading asgiref 2 to 3

Breaking2.3.2 → 3.13.0Breaking3Security2Platform12Deprecated3New12Changed19Fixed46Other2

Full comparisonBack to asgiref
BreakingUpgrade verdict

3 breaking changes and 12 platform requirement changes and 2 security fixes.

In plain terms
  • The ASGI_THREADS environment variable no longer configures the thread pool. Servers or applications must set the default executor themselves when setting up the event loop at startup.
  • The library now follows a newer version of the ASGI standard, so code written for the old standard may need updating.
  • Accessing attributes on Local is now much faster, but you can no longer subclass Local; doing so raises a TypeError.
  • The package now works on Python 3.15.
Must act Top 5 of 20 that need code or config changes

Requires Python >=3.11 from 3.13.0 (none stated before).

Drops async-timeout.

Installs 0 packages in all (was 1).

What you must change

Breaking3
Removes support for the ASGI_THREADS environment variable used by SyncToAsync.
ASGI_THREADSSyncToAsync
3.6.0CHANGELOG.txtSummarizedView source
Updates the package to match the new ASGI 3.0 spec.
3.0.0CHANGELOG.txtSummarizedView source
Makes Local attribute access 2-3x faster via internal specialisations and marks Local as @final, raising TypeError on subclassing.
Localthread_critical
3.13.0CHANGELOG.txtSummarizedView source
Security2
Fixes CVE-2025-14550, a DoS vector in WsgiToAsgi from malicious requests with many repeated header values.
asgiref.wsgi.WsgiToAsgi
3.11.1CHANGELOG.txtSummarizedView source
Makes header handling more efficient and adds a duplicate_header_limit parameter to WsgiToAsgi, defaulting to 100.
WsgiToAsgiduplicate_header_limit
3.11.1CHANGELOG.txtSummarizedView source
Platform12
Adds support for Python 3.15.
3.13.0CHANGELOG.txtSummarizedView source
Drops support for EOL Python 3.10.
3.13.0CHANGELOG.txtSummarizedView source
Drops support for end-of-life Python 3.9.
3.12.0CHANGELOG.txtSummarizedView source
Adds support for Python 3.14.
3.9.2CHANGELOG.txtSummarizedView source
Adds support for Python 3.13.
3.9.0CHANGELOG.txtSummarizedView source
Drops support for end-of-life Python 3.8.
3.9.0CHANGELOG.txtSummarizedView source
Adds support for Python 3.12.
3.8.0CHANGELOG.txtSummarizedView source
Drops support for end-of-life Python 3.7.
3.8.0CHANGELOG.txtSummarizedView source
Contextvars are now required for the implementation of sync as Python 3.6 is no longer supported.
sync
3.7.0CHANGELOG.txtSummarizedView source
Drops support for Python 3.6 and switches asyncio calls to modern APIs only.
3.5.0CHANGELOG.txtSummarizedView source
Drops Python 3.5 support.
3.3.2CHANGELOG.txtSummarizedView source
Adds support and testing for Python 3.8.
3.2.3CHANGELOG.txtSummarizedView source

Deprecations to plan for

Deprecated3
Deprecates asgiref.timeout.timeout, to be removed in a future release; use asyncio.timeout() instead.
asgiref.timeout.timeoutasyncio.timeout()
3.13.0CHANGELOG.txtSummarizedView source
Deprecates the loop argument to asgiref.timeout.timeout; the running event loop is used by default.
asgiref.timeout.timeoutloop
3.6.0CHANGELOG.txtSummarizedView source
Renames all Websocket* types to WebSocket; old names work until 3.5.0 but raise deprecation warnings.
WebsocketScopeWebSocketScope
3.4.0CHANGELOG.txtSummarizedView source