changeSet not recognised using gradle plugin

Liquibase Development
1

I’m trying to upgrade our dependency from “org.liquibase:liquibase-core:4.6.0’” to “org.liquibase:liquibase-core:4.23.0”. But facing new errors when running “./gradlew bootRun”

Caused by: liquibase.exception.CommandExecutionException: 
liquibase.exception.ChangeLogParseException:
Error parsing classpath:/db/changelog/db.changelog-master.yaml : 
Error parsing db/changelog/versions/ABC-234/db.changelog.yaml : 
Error parsing db/changelog/versions/ABC-234/db.changelog.yaml: 
Unknown change type 'changeSet'. 
Check for spelling or capitalization errors and missing extensions such as liquibase-commercial.

db.changelog includes multiple changeSet ’ s and also nested changeSet in rollback tag.

Any clues, on how to resolve this?

Thanks
Abhi