---
title: Migrate legacy A/B test
slug: feature-experimentation/docs/migrate-legacy-a-b-test
docTags: 
createdAt: 2026-08-05T20:39:53.000Z
---

- Optimizely Feature Experimentation
- Optimizely Full Stack (Legacy)

This topic maps each corresponding UI element for an [A/B test in legacy Full Stack](docId:6_ik6SSz-WyJLWuCQw7BT) to an [A/B test in Feature Experimentation](docId:8pnfCv-sR37goLcxTtCPv). A Multi-Armed Bandit maps similarly in Feature Experimentation. For more information, see [Feature Experimentation application migration](docId\:bykQnE4aGRkC5WXhU6Yi5).

:::hint{type="info"}
**Note**

Optimizely creates one A/B test for each environment in Feature Experimentation. 
The original (Full Stack) experiment ID is only preserved for production.
:::

## Variations

1. The legacy Optimizely Full Stack Experimentation A/B test's experiment name becomes the A/B test rule's name attached to the flag in Optimizely Feature Experimentation.

   :::hint{type="info"}
   **Note**

   Because there is no corresponding name for a rule in Full Stack, Feature Experimentation creates a name based on the audience.
   :::
2. The A/B test rule's flag key is a randomly generated GUID.
3. The legacy experiment state **Paused** or **Running** becomes the A/B test rule's state.
4. The legacy experiment's variations and traffic distribution percentages become the A/B test rule's variation traffic percentage.

- Legacy Full Stack

  ![fs.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/u4wIcsK_UrMa48E2qQ1Lu-20260720-145822.png)
- Feature Experimentation

  ![fx.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/AdfAuwyfLHgHEZPTXyN38-20260720-145822.png)

## Allowlist (previously known as whitelist)

:::hint{type="info"}
**Note**

[Whitelist](docId:6_ik6SSz-WyJLWuCQw7BT) was renamed to allowlist in Optimizely Feature Experimentation.
:::

1. A legacy A/B test's whitelist becomes the Feature Experimentation A/B test rule's [allowlist](docId:5UlaFy9bllyJz-PW39UtC).

- Legacy Full Stack Experimentation

  ![a-b-test-whitelist.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/5OPNHA0iLOtWFq5wDNscE-20260720-145822.png)
- Optimizely Feature Experimentation

  ![fx-allowlist.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/3qPxai7_h7dWFEQS2xw93-20260720-145822.png)

## Audiences

1. A legacy A/B test's audience becomes the A/B test rule's audience.  

- Legacy Full Stack

  ![audiences-ab-fs.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/slhFBGU5F-vOI46X_Bzvt-20260720-145822.png)
- Optimizely Feature Experimentation

  ![audiences-ab-fx.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/6kOdg2XSkG5EvD0q96DXb-20260720-145822.png)

## Traffic allocation

1. The legacy A/B test's traffic allocation percentage becomes the A/B test rule's **Percentage Included**.

- Legacy Full Stack

  ![traffic-allocation-ab-fs.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/5df6dY0C2hpzzjranSToZ-20260720-145822.png)
- Optimizely Feature Experimentation

  ![traffic-allocation-ab-fx.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/WWuPyzqyCsDpwbH9q1oci-20260720-145822.png)

## Metrics

1. The legacy A/B test's metrics become the A/B test rule's metrics. 

- Legacy Full Stack

  ![metrics-ab-fs.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/I18nCdZS2bweP16Z8jYjY-20260720-145822.png)
- Optimizely Feature Experimentation

  ![metrics-ab-fx.png](https://api.archbee.com/api/optimize/BrbvVORKJ5iIeSMZye5kI/TnvYk0ZW_epPwKrIVNG_1-20260720-145822.png)