# Update the mapping of your feed When you create a new feed, the latest available mapping for that channel is saved to that feed. The mapping determines which fields are mandatory, recommended and optional for the channel. To ensure that changes to the specification of the export feed don't break your existing feeds, we keep this mapping the same as when you first created the feed. Specifications of channels change over time, so if you want the [**Mapping** step](https://helpcenter.channable.com/list-advertise/list-on-channels/set-up-a-feed/set-up-a-feed-mapping-step) of an export feed to represent the latest specification, you must update the mapping of your feed. Follow these steps to update the mapping of an export feed: 1. Navigate to **Feeds > \[Your feed]**(the feed that you want to update the mapping for). 2. Go to **Settings**. 3. Click on the gear dropdown and select **Update mapping**. 4. To confirm, click **Update mapping** in the pop-up. The mapping of the fields in the **Mapping** step is now updated. This means that Channable will check the existing fields that are mapped in the feed template for any changes or updates. These changes and additions will then appear in the **Mapping** step. {% hint style="info" %} **Note:** Updating the mapping of an export feed will **not** remove export mapping fields you have connected to your own fields in the **Mapping** step. If a field no longer exists in the channel specification but you are using it, it will be changed into a user-provided (custom) field. {% endhint %}