* Added the hash function `murmurHash2_32`[#2756](https://github.com/yandex/ClickHouse/pull/2756).
### Improvements:
* Now you can use the `from_env` attribute to set values in config files from environment variables [#2741](https://github.com/yandex/ClickHouse/pull/2741).
* Added case-insensitive versions of the `coalesce`, `ifNull`, and `nullIf functions`[#2752](https://github.com/yandex/ClickHouse/pull/2752).
### Bug fixes:
* Fixed a possible bug when starting a replica [#2759](https://github.com/yandex/ClickHouse/pull/2759).
## ClickHouse release 18.4.0, 2018-07-28
### New features:
* Added system tables: `formats`, `data_type_families`, `aggregate_function_combined`, `table_functions`, `table_engines`, `collections`[#2721](https://github.com/yandex/ClickHouse/pull/2721).
* Added the ability to use a table function instead of a table as an argument of a `remote` or `cluster table function`[#2708](https://github.com/yandex/ClickHouse/pull/2708).
* Support for `HTTP Basic` authentication in the replication protocol [#2727](https://github.com/yandex/ClickHouse/pull/2727).
* The `has` function now allows searching for a numeric value in an array of `Enum` values [Maxim Khrisanfov](https://github.com/yandex/ClickHouse/pull/2699).
* Support for adding arbitrary message separators when reading from `Kafka`[Amos Bird](https://github.com/yandex/ClickHouse/pull/2701).
### Improvements:
* The `ALTER TABLE t DELETE WHERE` query does not overwrite data chunks that were not affected by the WHERE condition [#2694](https://github.com/yandex/ClickHouse/pull/2694).
* The `use_minimalistic_checksums_in_zookeeper` option for `ReplicatedMergeTree` tables is enabled by default. This setting was added in version 1.1.54378, 2018-04-16. Versions that are older than 1.1.54378 can no longer be installed.
* Support for running `KILL` and `OPTIMIZE` queries that specify `ON CLUSTER`[Winter Zhang](https://github.com/yandex/ClickHouse/pull/2689).
### Bug fixes:
* Fixed the error `Column ... is not under an aggregate function and not in GROUP BY` for aggregation with an IN expression. This bug appeared in version 18.1.0. ([bbdd780b](https://github.com/yandex/ClickHouse/commit/bbdd780be0be06a0f336775941cdd536878dd2c2))
* Fixed a bug in the `windowFunnel aggregate function`[Winter Zhang](https://github.com/yandex/ClickHouse/pull/2735).
* Fixed a bug in the `anyHeavy` aggregate function ([a2101df2](https://github.com/yandex/ClickHouse/commit/a2101df25a6a0fba99aa71f8793d762af2b801ee))
* Fixed server crash when using the `countArray()` feature.
