Migration Truncate Data

Hi Everyone!

From the 3.x version when I use migration class, database table data deleted.
Even I add one column to a existing datatable all data truncated.
In the previous version that works good and column added, rows stay.

Can someone give advice?
(Environment: WIndows 7, Mysql 5.6)

I found the solution.
config/migrations $config['migration_version'] variable stay in a old version so downgrade every time the database.