Not able to drop a column from columnstore table

Off-Topic
1

ALTER TABLE table1 drop column col1 ;

it is throwing below error
Error Code: 1890. This version of MemSQL cannot perform an offline ALTER TABLE on a COLUMN STORE table. The requested ALTER TABLE cannot be performed online because it drops an index from a columnstore table.

2

You can’t drop a sort key column from a columnstore table. What was your DDL for the table (CREATE TABLE statement, and all CREATE INDEX statements)? And what version are you using? 7.1 let’s you drop columns with hash indexes using ALTER.