# Lens upgrades in AWS WA Tool
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The AWS Well-Architected Framework Lens and other lenses provided by AWS are updated as new services are introduced, existing best practices for cloud-based systems are refined, and new best practices are added. When a new version of a lens is made available, AWS WA Tool is upgraded to reflect the latest best practices. Any new workloads that are defined use the new version of the lens.

A lens upgrade also occurs when a custom lens that you have applied to a workload or a review template has a new major version published.

A lens upgrade can consist of any combination of:
+ Adding new questions or best practices
+ Removing old questions or practices that are no longer recommended
+ Updating existing questions or best practices 
+ Adding or removing pillars

Your answers to existing questions are retained.

**Note**  
You cannot undo a lens upgrade. After a workload has been upgraded to the latest lens version, you cannot go back to the previous version of the lens.

# Determining which lens to upgrade in AWS WA Tool
<a name="lenses-selecting"></a>

You can find which workloads aren't using the most current lens version by viewing the **Notifications** page. 

The following information is displayed on the **Notifications** page for each workload:

**Resource**  
The name of the workload or review template.

**Resource type**  
The type of resource. This can be either **Workload** or **Review template**.

**Associated resource**  
The name of the lens.

**Notification type**  
The type of upgrade notification.  
+ **Not current** – The workload is using a version of the lens that is no longer current. Upgrade to the current lens version for better guidance.
+ **Deprecated** – The workload is using a version of the lens that no longer reflects best practices. Upgrade to the current lens version.
+ **Deleted** – The workload is using a lens that has been deleted by its owner.

**Version in use**  
The lens version currently used for the workload.

**Current available version**  
The lens version available for upgrade, or **None** if the lens has been deleted.

To upgrade the lens associated with a workload, select the workload and choose **Upgrade lens version**.

# Upgrading a lens in AWS WA Tool
<a name="lenses-upgrading"></a>

Lenses can be upgraded for workloads and review templates.

**Note**  
You can't undo a lens upgrade. After a workload or review template has been upgraded to the latest lens version, you can't go back to the previous version of the lens.

**Upgrading a lens for a workload**

1. On the **Notifications** page, select a workload to upgrade, and choose **Upgrade lens version**. Information about what changed in each pillar is displayed.
**Note**  
You can also choose **View available upgrades** from the workload **Overview** tab.

1. Before upgrading a lens for a workload, a milestone is created to save the state of your existing workload for future reference. Enter a unique name for the milestone in the **Milestone name** field.

1. Select the **Confirmation** box next to **I understand and accept these changes** and choose **Save**.

Once the lens is upgraded, you can view the previous version of the lens from the **Milestones** tab. 

**Upgrading a lens for a review template**

1. To upgrade the lens for a review template, choose

1. On the **Notifications** page, select a review template to upgrade, and choose **Upgrade lens version**. Information about what changed in each pillar is displayed.
**Note**  
You can also choose **View available upgrades** from the review template **Overview** tab.

1. Select the **Confirmation** box next to **I understand and accept these changes** and choose **Upgrade and edit template answers** to adjust answers to best practice questions for your review template, or **Upgrade** to upgrade the lens without adjusting your template answers.