The item tag "new" is auto assigned when the new product identification tag is enabled and a new item is uploaded from your ERP to DC. This tagging process is used to let a user know that the item has newly entered DemandCaster and may require its settings modified.
To change the setting of the item, follow the steps in the article How to Change the Planning Settings for Multiple Items at Once (Multi-Edit)
Please note that once a tag is assigned to a item, it will not be automatically removed since a user may forget to change settings or wants to do it later. It is strongly recommended to remove the "new" tag upon confirming or changing the items planning settings.
To remove the tag, follow the steps in the article "How to Add or Remove Item Tags"