JSON Column issue with version 2.0.50

I am not a Yii expert so please forgive me if this is something obvious to you.

Recently, with version 2.0.50, I noticed this change:
Enh #20171: Support JSON columns for MariaDB 10.4 or higher

Is there a document that is updated somewhere on the site that explains this change in detail?

My issue with this change:

The form to add or edit a JSON (DB) column no longer works now because an array is now returned when it used to be a string. See the excerpt from the _form.php for the DB model where the attr column is a JSON column.

    <?= $form->field($model, 'attr')->textarea(['rows' => 6]) ?>