ALTER TABLE users DROP COLUMN IF EXISTS week_start_day;
ALTER TABLE users DROP COLUMN IF EXISTS date_format;
ALTER TABLE users DROP COLUMN IF EXISTS time_format;
ALTER TABLE users DROP COLUMN IF EXISTS default_event_duration_minutes;
ALTER TABLE users DROP COLUMN IF EXISTS default_reminder_minutes;
ALTER TABLE users DROP COLUMN IF EXISTS show_weekends;
ALTER TABLE users DROP COLUMN IF EXISTS working_hours_start;
ALTER TABLE users DROP COLUMN IF EXISTS working_hours_end;
ALTER TABLE users DROP COLUMN IF EXISTS notifications_email;