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### ClickHouse release 24.1, 2024-01-30. [Presentation](https://presentations.clickhouse.com/2024-release-24.1/), [Video](https://www.youtube.com/watch?v=pBF9g0wGAGs)[​](#a-id241a-clickhouse-release-241-2024-01-30 "Direct link to a-id241a-clickhouse-release-241-2024-01-30")

#### Backward Incompatible Change[​](#backward-incompatible-change-9 "Direct link to Backward Incompatible Change")

- The setting `print_pretty_type_names` is turned on by default. You can turn it off to keep the old behavior or `SET compatibility = '23.12'`. [#57726](https://github.com/ClickHouse/ClickHouse/pull/57726) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- The MergeTree setting `clean_deleted_rows` is deprecated, it has no effect anymore. The `CLEANUP` keyword for `OPTIMIZE` is not allowed by default (unless `allow_experimental_replacing_merge_with_cleanup` is enabled). [#58316](https://github.com/ClickHouse/ClickHouse/pull/58316) ([Alexander Tokmakov](https://github.com/tavplubix)).
- The function `reverseDNSQuery` is no longer available. This closes [#58368](https://github.com/ClickHouse/ClickHouse/issues/58368). [#58369](https://github.com/ClickHouse/ClickHouse/pull/58369) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Enable various changes to improve the access control in the configuration file. These changes affect the behavior, and you check the `config.xml` in the `access_control_improvements` section. In case you are not confident, keep the values in the configuration file as they were in the previous version. [#58584](https://github.com/ClickHouse/ClickHouse/pull/58584) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- Improve the operation of `sumMapFiltered` with NaN values. NaN values are now placed at the end (instead of randomly) and considered different from any values. `-0` is now also treated as equal to `0`; since 0 values are discarded, `-0` values are discarded too. [#58959](https://github.com/ClickHouse/ClickHouse/pull/58959) ([Raúl Marín](https://github.com/Algunenano)).
- The function `visibleWidth` will behave according to the docs. In previous versions, it simply counted code points after string serialization, like the `lengthUTF8` function, but didn't consider zero-width and combining characters, full-width characters, tabs, and deletes. Now the behavior is changed accordingly. If you want to keep the old behavior, set `function_visible_width_behavior` to `0`, or set `compatibility` to `23.12` or lower. [#59022](https://github.com/ClickHouse/ClickHouse/pull/59022) ([Alexey Milovidov](https://github.com/alexey-milovidov)).
- `Kusto` dialect is disabled until these two bugs will be fixed: [#59037](https://github.com/ClickHouse/ClickHouse/issues/59037) and [#59036](https://github.com/ClickHouse/ClickHouse/issues/59036). [#59305](https://github.com/ClickHouse/ClickHouse/pull/59305) ([Alexey Milovidov](https://github.com/alexey-milovidov)). Any attempt to use `Kusto` will result in exception.
- More efficient implementation of the `FINAL` modifier no longer guarantees preserving the order even if `max_threads = 1`. If you counted on the previous behavior, set `enable_vertical_final` to 0 or `compatibility` to `23.12`.

#### New Feature[​](#new-feature-11 "Direct link to New Feature")