Misc updates for Automatic AZ setting and stv1 retirement

Author: dlepow

articles/reliability/media/migrate-api-mgt/option-four-add-new-location.png

@@ -4,7 +4,7 @@ description: Learn how to migrate your Azure API Management instances to availab
 author: shaunjacob 
 ms.service: azure-api-management
 ms.topic: how-to
-ms.date: 10/16/2024
+ms.date: 05/09/2025
 ms.author: anaharris
 ms.custom: subject-reliability
 
@@ -18,38 +18,39 @@ The Azure API Management service supports [availability zones](../reliability/av
 
 * **Zone-redundant** - the gateway and the control plane of your API Management instance (management API, developer portal, Git configuration) are replicated across two or more physically separated zones within an Azure region. Zone redundancy provides resiliency and high availability to a service instance.
 
-This article describes four scenarios for migrating an API Management instance to availability zones. For more information about configuring API Management for high availability, see [Ensure API Management availability and reliability](../api-management/high-availability.md).
+This article describes three scenarios for migrating an API Management instance to availability zones. For more information about configuring API Management for high availability, see [Ensure API Management availability and reliability](../api-management/high-availability.md).
 
 [!INCLUDE [api-management-service-update-behavior](../../includes/api-management-service-update-behavior.md)]
 
 ## Prerequisites
 
 * To configure availability zones for API Management, your instance must be in one of the [Azure regions that support availability zones](regions-list.md).
 
-* If you don't have an API Management instance, create one by following the [Create a new Azure API Management instance by using the Azure portal](../api-management/get-started-create-service-instance.md) quickstart. Select the Premium service tier.
+* If you don't have an API Management instance, create one by following the [Create a new Azure API Management instance by using the Azure portal](../api-management/get-started-create-service-instance.md) quickstart. Select the **Premium** service tier.
 
-* If you have an existing API Management instance, make sure that it's in the Premium tier. If it isn't, [upgrade to the Premium tier](../api-management/upgrade-and-scale.md#change-your-api-management-service-tier).
+* If you have an existing API Management instance, make sure that it's in the **Premium** tier. If it isn't, [upgrade to the Premium tier](../api-management/upgrade-and-scale.md#change-your-api-management-service-tier).
 
 
 ## Downtime requirements
 
-There are no downtime requirements for any of the migration options.
+There are no gateway downtime requirements for any of the migration options.
 
 ## Considerations
 
-* Changes can take 15 to 45 minutes to apply. The API Management gateway can continue to handle API requests during this time.
-
 * When you're migrating an API Management instance that's deployed in an external or internal virtual network to availability zones, you can optionally specify a new public IP address resource. In an internal virtual network, the public IP address is used only for management operations, not for API requests. [Learn more about IP addresses of API Management](../api-management/api-management-howto-ip-addresses.md).
 
 * Migrating to availability zones or changing the configuration of availability zones triggers a public and private [IP address change](../api-management/api-management-howto-ip-addresses.md#changes-to-the-ip-addresses).
 
-* When you're enabling availability zones in a region, you configure API Management scale [units](../api-management/upgrade-and-scale.md) that you can distribute evenly across the zones. For example, if you configure two zones, you can configure two units, four units, or another multiple of two units. 
+* By default, API Management sets availability zones automatically to distribute your scale [units](../api-management/upgrade-and-scale.md) and adjust to changes in zone availability in the region. If you select specific zones, make sure the scale units distribute evenly across the zones. For example, if you select two specific zones, you can configure two units, four units, or another multiple of two units. 
+
+    >[!IMPORTANT] 
+    >If you select specific zones, your resources will be pinned to those zones. Should all your resources in the selected zones become unavailable, your API Management instance will be unavailable. 
 
     [!INCLUDE [api-management-az-notes](../../includes/api-management-az-notes.md)]
 
-* If you configured autoscaling for your API Management instance in the primary location, you might need to adjust your autoscale settings after configuring availability zones. The number of API Management units in autoscale rules and limits must be a multiple of the number of zones.
+* If you configured autoscaling for your API Management instance in the primary location, you might need to adjust your autoscale settings after selecting availability zones. If you select specific zones, the number of API Management units in autoscale rules and limits must be a multiple of the number of zones.  
 
-## Existing gateway location not injected in a virtual network
+## Existing gateway location not injected in a virtual network 
 
 To migrate an existing location of your API Management instance to availability zones when the instance is not injected in a virtual network:
 
@@ -61,40 +62,15 @@ To migrate an existing location of your API Management instance to availability
 
 1. In the **Units** box, select the number of scale [units](../api-management/upgrade-and-scale.md) that you want in the location.
 
-1. In the **Availability zones** box, select *Automatic*. 
-
->[!IMPORTANT] 
->If you select specific zones, your resources will be pinned to those zones. Should all your resources in the selected zones become unavailable, your API Management instance will be unavailable. 
+1. In the **Availability zones** box, leave the **Automatic** setting (recommended), or optionally select one or more zones. If you select specific zones, the number of units that you selected must distribute evenly across the availability zones. For example, if you selected three units, you would select three zones so that each zone hosts one unit. 
 
 1. Select **Apply**, and then select **Save**.
 
 :::image type="content" alt-text="Screenshot that shows selections for migrating an existing location of API Management instance that's not injected in a virtual network." source ="media/migrate-api-mgt/option-one-not-injected-in-vnet.png":::
 
-## Existing gateway location (stv1 platform) injected in a virtual network
-
-To migrate an existing location of your API Management instance to availability zones when the instance is currently injected in a virtual network and is currently hosted on the `stv1` platform, use the following steps. Migrating to availability zones also migrates the instance to the `stv2` platform.
-
-1. Create a new subnet and optional public IP address in the location to migrate to availability zones. Detailed requirements are in the [virtual networking guidance](../api-management/api-management-using-with-vnet.md?tabs=stv2#prerequisites).
-
-1. In the Azure portal, go to your API Management instance.
-
-1. On the **Deployment + infrastructure** menu, select **Locations**.
-
-1. In the **Location** box, select the location to be migrated. The location must support availability zones, as mentioned earlier in the [prerequisites](#prerequisites).
-
-1. In the **Units** box, select the number of scale [units](../api-management/upgrade-and-scale.md) that you want in the location.
-
-1. In the **Availability zones** box, select one or more zones. The number of units that you selected must be distributed evenly across the availability zones. For example, if you selected three units, select three zones so that each zone hosts one unit.
-
-1. In the respective boxes under **Network**, select the new subnet and optional public IP address in the location.
-
-1. Select **Apply**, and then select **Save**.
-
-:::image type="content" alt-text="Screenshot that shows selections for migrating an existing location of an API Management instance that's injected in a virtual network." source ="media/migrate-api-mgt/option-two-injected-in-vnet.png":::
-
-## Existing gateway location (stv2 platform) injected in a virtual network
+## Existing gateway location injected in a virtual network
 
-To migrate an existing location of your API Management instance to availability zones when the instance is currently injected in a virtual network and is already hosted on the `stv2` platform:
+To migrate an existing location of your API Management instance to availability zones when the instance is currently injected in a virtual network:
 
 1. In the Azure portal, go to your API Management instance.
 
@@ -104,19 +80,19 @@ To migrate an existing location of your API Management instance to availability
 
 1. In the **Units** box, select the number of scale [units](../api-management/upgrade-and-scale.md) that you want in the location.
 
-1. In the **Availability zones** box, select one or more zones. The number of units that you selected must be distributed evenly across the availability zones. For example, if you selected three units, select three zones so that each zone hosts one unit.
+1. In the **Availability zones** box, leave the **Automatic** setting (recommended), or optionally select one or more zones. If you select specific zones, the number of units that you selected must distribute evenly across the availability zones. For example, if you selected three units, you would select three zones so that each zone hosts one unit.
 
 1. In the **Public IP Address** box, optionally select a public IP address in the location.
 
 1. Select **Apply**, and then select **Save**.
 
-:::image type="content" alt-text="Screenshot that shows selections to migrate existing location of API Management instance (stv2 platform) that's injected in a virtual network." source ="media/migrate-api-mgt/option-three-stv2-injected-in-vnet.png":::
+:::image type="content" alt-text="Screenshot that shows selections to migrate existing location of API Management instance that's injected in a virtual network." source ="media/migrate-api-mgt/option-three-stv2-injected-in-vnet.png":::
 
 ## New gateway location
 
 To add a new location to your API Management instance and enable availability zones in that location:
 
-1. If your API Management instance is deployed in a virtual network in the primary location, set up a [virtual network](../api-management/api-management-using-with-vnet.md?tabs=stv2), subnet, and optional public IP address in any new location where you plan to enable availability zones.
+1. If your API Management instance is deployed in a virtual network in the primary location, set up a [virtual network](../api-management/api-management-using-with-vnet.md), subnet, and optional public IP address in any new location where you plan to enable availability zones.
 
 1. In the Azure portal, go to your API Management instance.
 
@@ -126,7 +102,7 @@ To add a new location to your API Management instance and enable availability zo
 
 1. In the **Units** box, select the number of scale [units](../api-management/upgrade-and-scale.md) that you want in the location.
 
-1. In the **Availability zones** box, select one or more zones. The number of units that you selected must be distributed evenly across the availability zones. For example, if you selected three units, select three zones so that each zone hosts one unit.
+In the **Availability zones** box, leave the **Automatic** setting (recommended), or optionally select one or more zones. If you select specific zones, the number of units that you selected must distribute evenly across the availability zones. For example, if you selected three units, you would select three zones so that each zone hosts one unit.
 
 1. If your API Management instance is deployed in a virtual network, use the boxes under **Network** to select the virtual network, subnet, and optional public IP address that are available in the location.