Alter a table created on an older version

created a table in version 1.0.2
upgraded crate to 1.1.3
upgraded crate d to 2.1.6

now when i alter a table using below command
alter table gra.testtable add column attributes[‘testing’] STRING;

i get below error

SQLActionException[SQLParseException: unknown setting [index.version.created] please check that any required plugins are installed, or check the breaking changes documentation for removed settings]

There were some bugs in the past related to ALTER TABLE on tables created in previous versions.

Could you try upgrading CrateDB to the latest 2.1 version (2.1.10) or even better, to 2.3.12?