v.21.1Backward Incompatible Changes

Removal of implicit substitutions file references from default config in ClickHouse update

incl references to substitutions file (/etc/metrika.xml) were removed from the default config (<remote_servers>, <zookeeper>, <macros>, <compression>, <networks>). If you were using substitutions file and were relying on those implicit references, you should put them back manually and explicitly by adding corresponding sections with incl="..." attributes before the update. See #18740 (alexey-milovidov).