* [10887](https://github.com/apache/incubator-superset/pull/10887): Breaking change: The custom cache backend changed in order to support the Flask-Caching factory method approach and thus must be registered as a custom type. See [here](https://flask-caching.readthedocs.io/en/latest/#custom-cache-backends) for specifics.
* [10674](https://github.com/apache/incubator-superset/pull/10674): Breaking change: PUBLIC_ROLE_LIKE_GAMMA was removed is favour of the new PUBLIC_ROLE_LIKE so it can be set it whatever role you want.
* [10590](https://github.com/apache/incubator-superset/pull/10590): Breaking change: this PR will convert iframe chart into dashboard markdown component, and remove all `iframe`, `separator`, and `markup` slices (and support) from Superset. If you have important data in those slices, please backup manually.
* [10567](https://github.com/apache/incubator-superset/pull/10567): Default WEBDRIVER_OPTION_ARGS are Chrome-specific. If you're using FF, should be `--headless` only
* [10241](https://github.com/apache/incubator-superset/pull/10241): change on Alpha role, users started to have access to "Annotation Layers", "Css Templates" and "Import Dashboards".
* [10324](https://github.com/apache/incubator-superset/pull/10324): Facebook Prophet has been introduced as an optional dependency to add support for timeseries forecasting in the chart data API. To enable this feature, install Superset with the optional dependency `prophet` or directly `pip install fbprophet`.
* [10320](https://github.com/apache/incubator-superset/pull/10320): References to blacklst/whitelist language have been replaced with more appropriate alternatives. All configs refencing containing `WHITE`/`BLACK` have been replaced with `ALLOW`/`DENY`. Affected config variables that need to be updated: `TIME_GRAIN_BLACKLIST`, `VIZ_TYPE_BLACKLIST`, `DRUID_DATA_SOURCE_BLACKLIST`.
* [10794](https://github.com/apache/incubator-superset/pull/10794): Breaking change: `uuid` python package is not supported on Jinja2 anymore, only uuid functions are exposed eg: `uuid1`, `uuid3`, `uuid4`, `uuid5`.
* [9964](https://github.com/apache/incubator-superset/pull/9964): Breaking change on Flask-AppBuilder 3. If you're using OAuth, find out what needs to be changed [here](https://github.com/dpgaspar/Flask-AppBuilder/blob/master/README.rst#change-log).
* [10233](https://github.com/apache/incubator-superset/pull/10233): a change which deprecates the `ENABLE_FLASK_COMPRESS` config option in favor of the Flask-Compress `COMPRESS_REGISTER` config option which serves the same purpose.
* [10222](https://github.com/apache/incubator-superset/pull/10222): a change which changes how payloads are cached. Previous cached objects cannot be decoded and thus will be reloaded from source.
* [10130](https://github.com/apache/incubator-superset/pull/10130): a change which deprecates the `dbs.perm` column in favor of SQLAlchemy [hybird attributes](https://docs.sqlalchemy.org/en/13/orm/extensions/hybrid.html).
* [10034](https://github.com/apache/incubator-superset/pull/10034): a change which deprecates the public security manager `assert_datasource_permission`, `assert_query_context_permission`, `assert_viz_permission`, and `rejected_tables` methods with the `raise_for_access` method which also handles assertion logic for SQL tables.
* [10031](https://github.com/apache/incubator-superset/pull/10030): a change which renames the following public security manager methods: `can_access_datasource` to `can_access_table`, `all_datasource_access` to `can_access_all_datasources`, `all_database_access` to `can_access_all_databases`, `database_access` to `can_access_database`, `schema_access` to `can_access_schema`, and
`datasource_access` to `can_access_datasource`. Regrettably it is not viable to provide aliases for the deprecated methods as this would result in a name clash. Finally the `can_access_table` (previously `can_access_database`) method signature has changed, i.e., the optional `schema` argument no longer exists.
* [10030](https://github.com/apache/incubator-superset/pull/10030): a change which renames the public security manager `schemas_accessible_by_user` method to `get_schemas_accessible_by_user`.
* [9786](https://github.com/apache/incubator-superset/pull/9786): with the upgrade of `werkzeug` from version `0.16.0` to `1.0.1`, the `werkzeug.contrib.cache` module has been moved to a standalone package [cachelib](https://pypi.org/project/cachelib/). For example, to import the `RedisCache` class, please use the following import: `from cachelib.redis import RedisCache`.
* [9794](https://github.com/apache/incubator-superset/pull/9794): introduces `create view as` functionality in the sqllab. This change will require the `query` table migration and potential service downtime as that table has quite some traffic.
* [9572](https://github.com/apache/incubator-superset/pull/9572): a change which by default means that the Jinja `current_user_id`, `current_username`, and `url_param` context calls no longer need to be wrapped via `cache_key_wrapper` in order to be included in the cache key. The `cache_key_wrapper` function should only be required for Jinja add-ons.
* [8867](https://github.com/apache/incubator-superset/pull/8867): a change which adds the `tmp_schema_name` column to the `query` table which requires locking the table. Given the `query` table is heavily used performance may be degraded during the migration. Scheduled downtime may be advised.
* [9238](https://github.com/apache/incubator-superset/pull/9238): the config option `TIME_GRAIN_FUNCTIONS` has been renamed to `TIME_GRAIN_EXPRESSIONS` to better reflect the content of the dictionary.
* [8699](https://github.com/apache/incubator-superset/pull/8699): A `row_level_security_filters`
table has been added, which is many-to-many with `tables` and `ab_roles`. The applicable filters
are added to the sqla query, and the RLS ids are added to the query cache keys. If RLS is enabled in config.py (`ENABLE_ROW_LEVEL_SECURITY = True`; by default, it is disabled), they can be
* [5933](https://github.com/apache/incubator-superset/pull/5933)/[6078](https://github.com/apache/incubator-superset/pull/6078): changes which add schema and table metadata cache timeout logic at the database level. If left undefined caching of metadata is disabled.
* Superset 0.28 deprecates the `median` cluster label aggregator for mapbox visualizations. This particular aggregation is not supported on mapbox visualizations going forward.
* [9825](https://github.com/apache/incubator-superset/pull/9825): Support for Excel sheet upload added. To enable support, install Superset with the optional dependency `excel`