### ClickHouse release v20.8.7.15-lts FIXME as compared to v20.8.6.6-lts

#### Improvement
* Backported in [#17029](https://github.com/ClickHouse/ClickHouse/issues/17029): Make it possible to connect to `clickhouse-server` secure endpoint which requires SNI. This is possible when `clickhouse-server` is hosted behind TLS proxy. [#16938](https://github.com/ClickHouse/ClickHouse/pull/16938) ([filimonov](https://github.com/filimonov)).

#### Bug Fix
* Backported in [#15676](https://github.com/ClickHouse/ClickHouse/issues/15676): Query is finished faster in case of exception. Cancel execution on remote replicas if exception happens. [#15578](https://github.com/ClickHouse/ClickHouse/pull/15578) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#17106](https://github.com/ClickHouse/ClickHouse/issues/17106): fixes [#16574](https://github.com/ClickHouse/ClickHouse/issues/16574) fixes [#16231](https://github.com/ClickHouse/ClickHouse/issues/16231) fix remote query failure when using 'if' suffix aggregate function. [#16610](https://github.com/ClickHouse/ClickHouse/pull/16610) ([Winter Zhang](https://github.com/zhang2014)).
* Backported in [#16761](https://github.com/ClickHouse/ClickHouse/issues/16761): This will fix optimize_read_in_order/optimize_aggregation_in_order with max_threads>0 and expression in ORDER BY. [#16637](https://github.com/ClickHouse/ClickHouse/pull/16637) ([Azat Khuzhin](https://github.com/azat)).
* Backported in [#16738](https://github.com/ClickHouse/ClickHouse/issues/16738): Fix `IN` operator over several columns and tuples with enabled `transform_null_in` setting. Fixes [#15310](https://github.com/ClickHouse/ClickHouse/issues/15310). [#16722](https://github.com/ClickHouse/ClickHouse/pull/16722) ([Anton Popov](https://github.com/CurtizJ)).
* Backported in [#17021](https://github.com/ClickHouse/ClickHouse/issues/17021): Fix crash when using `any` without any arguments. This is for [#16803](https://github.com/ClickHouse/ClickHouse/issues/16803) . cc @azat. [#16826](https://github.com/ClickHouse/ClickHouse/pull/16826) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#16880](https://github.com/ClickHouse/ClickHouse/issues/16880): Abort multipart upload if no data was written to WriteBufferFromS3. [#16840](https://github.com/ClickHouse/ClickHouse/pull/16840) ([Pavel Kovalenko](https://github.com/Jokser)).
* Backported in [#16950](https://github.com/ClickHouse/ClickHouse/issues/16950): Prevent clickhouse server crashes when using TimeSeriesGroupSum. [#16865](https://github.com/ClickHouse/ClickHouse/pull/16865) ([filimonov](https://github.com/filimonov)).
* Backported in [#17077](https://github.com/ClickHouse/ClickHouse/issues/17077): Fix possible error `Illegal type of argument` for queries with `ORDER BY`. Fixes [#16580](https://github.com/ClickHouse/ClickHouse/issues/16580). [#16928](https://github.com/ClickHouse/ClickHouse/pull/16928) ([Nikolai Kochetov](https://github.com/KochetovNicolai)).
* Backported in [#17007](https://github.com/ClickHouse/ClickHouse/issues/17007): Install script should always create subdirs in config folders. This is only relevant for Docker build with custom config. [#16936](https://github.com/ClickHouse/ClickHouse/pull/16936) ([filimonov](https://github.com/filimonov)).
* Backported in [#17011](https://github.com/ClickHouse/ClickHouse/issues/17011): Fix possible server crash after `ALTER TABLE ... MODIFY COLUMN ... NewType` when `SELECT` have `WHERE` expression on altering column and alter doesn't finished yet. [#16968](https://github.com/ClickHouse/ClickHouse/pull/16968) ([Amos Bird](https://github.com/amosbird)).
* Backported in [#17040](https://github.com/ClickHouse/ClickHouse/issues/17040): Reresolve the IP of the `format_avro_schema_registry_url` in case of errors. [#16985](https://github.com/ClickHouse/ClickHouse/pull/16985) ([filimonov](https://github.com/filimonov)).
* Backported in [#17171](https://github.com/ClickHouse/ClickHouse/issues/17171): Fix bug when `ON CLUSTER` queries may hang forever for non-leader ReplicatedMergeTreeTables. [#17089](https://github.com/ClickHouse/ClickHouse/pull/17089) ([alesapin](https://github.com/alesapin)).