pypi / flask-caching

flask-caching

What changed in flask-caching 2, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-25.

9 breaking14 new APIs and options2 behavior and defaults2 tooling9 fixes and other

See which of these apply to your code, ranked, in your agent:

npx @unstale/cli init

@unstale/cli 0.2.6 on npm

flask-caching 236 changes

Breaking changes 9

View arguments named path or query_args are no longer treated as explicit make_cache_key() arguments of the same name.
2.5.1release notes
The Jinja tag no longer propagates backend errors; if the cache is unavailable, it renders the block normally.
2.5.0release notes
The default hash method changes from hashlib.md5 to hashlib.sha256, making earlier cache entries obsolete; configure hashlib.md5 to retain the old method.
2.5.0release notes
Removes support for the deprecated lowercase backend names null, simple, filesystem, redis, redissentinel, rediscluster, uwsgi, memcached, gaememcached, saslmemcached, and spreadsaslmemcached.
2.5.0release notes
Caches an HTTPException raised by the view and re-raises it on a cache hit; use response_filter to keep the exception out of the cache.
2.5.0release notes
The minimum required cachelib version is 0.17.0.
2.5.0release notes
Uses cachelib's delete_many behavior: nonexistent keys count as deleted, and with CACHE_IGNORE_ERRORS=False a RuntimeError is raised if a key could not be deleted.
2.5.0release notes
forced_update callbacks are called once per decorated function call rather than during key creation and again before cache lookup.
2.5.0release notes
Support for Python 3.10 is dropped.
2.5.0release notes

New APIs and options 14

Adds a FileSystemCache configuration option to select a different hash function for cache keys.
2.5.0release notes
Adds a configuration option to set the hash method used for cache keys created by @cached and @memoize.
2.5.0release notes
Adds a configuration option to set the cachelib serializer used by the backend.
2.5.0release notes
Signals are sent for cache hits and misses.
2.5.0release notes
Cachelib backends can now be configured directly using a cachelib class path, such as cachelib.ValkeyCache.
2.5.0release notes
Adds Cache.delete_cached() to support deleting views decorated with cached(query_string=True).
2.5.0release notes
Adds an is_stale option called on a cache hit with the cached value to determine whether the cache is stale; it can be combined with forced_update.
2.5.0release notes
Timeouts can now be specified with datetime.timedelta.
2.5.0release notes
Adds the path argument to support deleting views decorated with cached(query_string=True).
2.5.0release notes
Adds the query_args argument to support deleting views decorated with cached(query_string=True).
2.5.0release notes
Adds pool_blocking to make MemcachedCache backends thread-safe.
2.5.0release notes
Adds pool_size to make MemcachedCache backends thread-safe.
2.5.0release notes
Adds an is_stale option called on a cache hit with the cached value to determine whether the cache is stale; it can be combined with forced_update.
2.5.0release notes
Forwards kwargs to RedisCluster.from_url, allowing callers to pass arguments through.
2.4.1release notes

Behavior and default changes 2

CACHE_IGNORE_ERRORS now applies to every backend instead of only SimpleCache and FileSystemCache.
2.5.0release notes
SimpleCache is now thread-safe, using an RLock for all operations.
2.5.0release notes

Tooling 2

Preserves the wrapped function's signature and exposes uncached, cache_timeout, and make_cache_key to type checkers.
2.5.0release notes
Preserves the wrapped function's signature and exposes uncached, cache_timeout, make_cache_key, and delete_memoized to type checkers.
2.5.0release notes

Fixes and other changes 9

For a bound method, delete_memoized now takes the instance from the method, so passing obj.method and arguments deletes that method's cache.
2.5.0release notes
Includes key_prefix when building query-string cache keys.
2.5.0release notes
Stops response_hit_indication=True from appending a new after_request function to the app on every request.
2.5.0release notes
Fixes __caching_id__ so it can be used; @memoize no longer silently ignores it and runs the function uncached.
2.5.0release notes
Fixes views returning iterators of strings so rendered templates are not returned as a list of JSON strings.
2.5.0release notes
Fixes cache-key collisions between a falsy parameter default and None, which could return the wrong cached result.
2.5.0release notes
Refreshes the memoize version key's timeout whenever an entry is written, using that entry's own timeout, to avoid invalidating the function's entire cache.
2.5.0release notes
Fixes the CachedResponse.__init__ typing for mypy --strict.
2.4.1release notes
Fixes memoize and cached TYPE_CHECKING annotations under Python 3.14.
2.4.1release notes