# Flask changelog > A lightweight WSGI web application framework. - Vendor: Pallets - Category: Frameworks & Libraries - Official site: https://flask.palletsprojects.com - Tracked by: What's New (https://whatsnew.fyi/product/flask) - Harvested from: GitHub (pallets/flask) - Entries below: 10 (newest first) What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog. ## Releases ### 3.1.3 - Date: 2026-02-19 - Version: 3.1.3 - Original notes: https://github.com/pallets/flask/releases/tag/3.1.3 - Permalink: https://whatsnew.fyi/product/flask/releases/3.1.3 - **security** — The session is marked as accessed for operations that only access the keys but not the values, such as `in` and `len` This is the Flask 3.1.3 security fix release, which fixes a security issue but does not otherwise change behavior and should not result in breaking changes compared to the latest feature release. PyPI: https://pypi.org/project/Flask/3.1.3/ Changes: https://flask.palletsprojects.com/page/changes/#version-3-1-3 - The session is marked as accessed for operations that only access the keys but not the values, such as `in` and `len`. [GHSA-68rp-wp8r-4726](https://github.com/pallets/flask/security/advisories/GHSA-68rp-wp8r-4726) ### 3.1.2 - Date: 2025-08-19 - Version: 3.1.2 - Original notes: https://github.com/pallets/flask/releases/tag/3.1.2 - Permalink: https://whatsnew.fyi/product/flask/releases/3.1.2 This is the Flask 3.1.2 fix release, which fixes bugs but does not otherwise change behavior and should not result in breaking changes compared to the latest feature release. PyPI: https://pypi.org/project/Flask/3.1.2/ Changes: https://flask.palletsprojects.com/page/changes/#version-3-1-2 Milestone: https://github.com/pallets/flask/milestone/38?closed=1 - `stream_with_context` does not fail inside async views. #5774 - When using `follow_redirects` in the test client, the final state of `session` is correct. #5786 - Relax type hint for passing bytes IO to `send_file`. #5776 ### 3.1.1 - Date: 2025-05-13 - Version: 3.1.1 - Original notes: https://github.com/pallets/flask/releases/tag/3.1.1 - Permalink: https://whatsnew.fyi/product/flask/releases/3.1.1 This is the Flask 3.1.1 fix release, which fixes bugs but does not otherwise change behavior and should not result in breaking changes compared to the latest feature release. PyPI: https://pypi.org/project/Flask/3.1.1/ Changes: https://flask.palletsprojects.com/en/stable/changes/#version-3-1-1 Milestone https://github.com/pallets/flask/milestone/36?closed=1 - Fix signing key selection order when key rotation is enabled via `SECRET_KEY_FALLBACKS`. GHSA-4grg-w6v8-c28g - Fix type hint for `cli_runner.invoke`. #5645 - `flask --help` loads the app and plugins first to make sure all commands are shown. #5673 - Mark sans-io base class as being able to handle views that return `AsyncIterable`. This is not accurate for Flask, but makes typing easier for Quart. #5659 ### 3.1.0 - Date: 2024-11-13 - Version: 3.1.0 - Original notes: https://github.com/pallets/flask/releases/tag/3.1.0 - Permalink: https://whatsnew.fyi/product/flask/releases/3.1.0 This is the Flask 3.1.0 feature release. A feature release may include new features, remove previously deprecated code, add new deprecations, or introduce potentially breaking changes. We encourage everyone to upgrade, and to use a tool such as [pip-tools](https://pypi.org/project/pip-tools/) to pin all dependencies and control upgrades. Test with warnings treated as errors to be able to adapt to deprecation warnings early. PyPI: https://pypi.org/project/Flask/3.1.0/ Changes: https://flask.palletsprojects.com/en/stable/changes/#version-3-1-0 Milestone: https://github.com/pallets/flask/milestone/33?closed=1 - Drop support for Python 3.8. #5623 - Update minimum dependency versions to latest feature releases. Werkzeug >= 3.1, ItsDangerous >= 2.2, Blinker >= 1.9. #5624, #5633 - Provide a configuration option to control automatic option responses. #5496 - `Flask.open_resource`/`open_instance_resource` and `Blueprint.open_resource` take an `encoding` parameter to use when opening in text mode. It defaults to `utf-8`. #5504 - `Request.max_content_length` can be customized per-request instead of only through the `MAX_CONTENT_LENGTH` config. Added `MAX_FORM_MEMORY_SIZE` and `MAX_FORM_PARTS` config. Added documentation about resource limits to the security page. #5625 - Add support for the `Partitioned` cookie attribute (CHIPS), with the `SESSION_COOKIE_PARTITIONED` config. #5472 - `-e path` takes precedence over default `.env` and `.flaskenv` files. `load_dotenv` loads default files in addition to a path unless `load_defaults=False` is passed. #5628 - Support key rotation with the `SECRET_KEY_FALLBACKS` config, a list of old secret keys that can still be used for unsigning. Extensions will need to add support. #5621 - Fix how setting `host_matching=True` or `subdomain_matching=False` interacts with `SERVER_NAME`. Setting `SERVER_NAME` no longer restricts requests to only that domain. #5553 - `Request.trusted_hosts` is checked during routing, and can be set through the `TRUSTED_HOSTS` config. #5636 ### 3.0.3 - Date: 2024-04-07 - Version: 3.0.3 - Original notes: https://github.com/pallets/flask/releases/tag/3.0.3 - Permalink: https://whatsnew.fyi/product/flask/releases/3.0.3 This is a fix release for the 3.0.x feature branch. PyPI: https://pypi.org/project/Flask/3.0.3/ Changes: https://flask.palletsprojects.com/en/3.0.x/changes/#version-3-0-3 Milestone: https://github.com/pallets/flask/milestone/35?closed=1 - The default `hashlib.sha1` may not be available in FIPS builds. Don't access it at import time so the developer has time to change the default. #5448 - Don't initialize the `cli` attribute in the sansio scaffold, but rather in the `Flask` concrete class. #5270 ### 3.0.2 - Date: 2024-02-03 - Version: 3.0.2 - Original notes: https://github.com/pallets/flask/releases/tag/3.0.2 - Permalink: https://whatsnew.fyi/product/flask/releases/3.0.2 This is a fix release for the 3.0.x feature release branch. It fixes bugs but does not otherwise change behavior and should not result in breaking changes. * Changes: https://flask.palletsprojects.com/en/3.0.x/changes/#version-3.0.2 * Milestone: https://github.com/pallets/flask/milestone/34?closed=1 * PyPI: https://pypi.org/project/Flask/3.0.2/ ### 3.0.1 - Date: 2024-01-18 - Version: 3.0.1 - Original notes: https://github.com/pallets/flask/releases/tag/3.0.1 - Permalink: https://whatsnew.fyi/product/flask/releases/3.0.1 This is a fix release for the 3.0.x feature release branch. Fixes an issue where using other JSON providers, such as `flask-orjson`, previously caused loaded session data to have an incorrect format in some cases. * Changes: https://flask.palletsprojects.com/en/3.0.x/changes/#version-3-0-1 * Milestone: https://github.com/pallets/flask/milestone/32?closed=1 * PyPI: https://pypi.org/project/Flask/3.0.1/ ### 3.0.0 - Date: 2023-09-30 - Version: 3.0.0 - Original notes: https://github.com/pallets/flask/releases/tag/3.0.0 - Permalink: https://whatsnew.fyi/product/flask/releases/3.0.0 This is a feature release, which includes new features, removes previously deprecated code, and adds new deprecations. The 3.0.x branch is now the supported fix branch, the 2.3.x branch will become a tag marking the end of support for that branch. We encourage everyone to upgrade, and to use a tool such as [pip-tools](https://pypi.org/project/pip-tools/) to pin all dependencies and control upgrades. Test with warnings treated as errors to be able to adapt to deprecation warnings early. * Changes: https://flask.palletsprojects.com/en/3.0.x/changes/#version-3-0-0 * Milestone: https://github.com/pallets/flask/milestone/20?closed=1 ### 2.3.3 - Date: 2023-08-21 - Version: 2.3.3 - Original notes: https://github.com/pallets/flask/releases/tag/2.3.3 - Permalink: https://whatsnew.fyi/product/flask/releases/2.3.3 This is a fix release for the 2.3.x feature branch. - Changes: https://flask.palletsprojects.com/en/2.3.x/changes/#version-2-3-3 - Milestone: https://github.com/pallets/flask/milestone/31?closed=1 ### 2.2.5 - Date: 2023-05-02 - Version: 2.2.5 - Original notes: https://github.com/pallets/flask/releases/tag/2.2.5 - Permalink: https://whatsnew.fyi/product/flask/releases/2.2.5 This is a security fix release for the 2.2.x release branch. Note that 2.3.x is the currently supported release branch; please upgrade to the latest version if possible. * Security advisory: https://github.com/pallets/flask/security/advisories/GHSA-m2qf-hxjv-5gpq, CVE-2023-30861 * Changes: https://flask.palletsprojects.com/en/2.2.x/changes/#version-2-2-5 * Milestone: https://github.com/pallets/flask/milestone/30?closed=1