DOC-178 update upgrade guide

Author: markzegarelli

src/_data/sidenav/strat.yml

@@ -93,8 +93,8 @@ sections:
     title: Analytics.js (Javascript) Source
   - path: /connections/sources/catalog/libraries/website/javascript/ajs-classic
     title: Analytics.js Classic
-  - path: /connections/sources/catalog/libraries/website/javascript/migrate-to-ajs2
-    title: Migrate to Analytics.js 2.0
+  - path: /connections/sources/catalog/libraries/website/javascript/upgrade-to-ajs2
+    title: Upgrade to Analytics.js 2.0
   - path: /connections/sources/catalog/libraries/website/javascript/supported-browsers
     title: Analytics.js supported browsers
   - path: /connections/sources/catalog/libraries/website/javascript/quickstart

src/connections/sources/catalog/libraries/website/javascript/index.md

@@ -36,6 +36,10 @@ Analytics.js 2.0 introduces new ways for developers to augment events throughout
 
 Read through the [Analytics.js QuickStart Guide](/docs/connections/sources/catalog/libraries/website/javascript/quickstart/) which explains how to add Analytics.js to your site in just a few minutes. Once you've installed the library, read on for the detailed API reference!
 
+### Upgrade your existing Javascript sources
+
+For information about upgrading your existing javascript sources, see [Upgrade to A.js 2.0](/docs/connections/sources/catalog/libraries/website/javascript/upgrade-to-ajs2).
+
 ## Basic tracking methods
 
 The basic tracking methods below are the building blocks of your Segment tracking. They include [Identify](#identify), [Track](#track), [Page](#page), [Group](#group), and [Alias](#alias), as described below.

src/connections/sources/catalog/libraries/website/javascript/migrate-to-ajs2.md renamed to src/connections/sources/catalog/libraries/website/javascript/upgrade-to-ajs2.md

@@ -1,24 +1,24 @@
 ---
-title: Migrate to A.js 2.0
+title: Upgrade to A.js 2.0
 strat: ajs
 ---
 
-Analytics.js 2.0 is fully backward compatible with Analytics.js Classic. To migrate your sources, follow the manual upgrade steps below, or see the schedule for automatic migration.
+Analytics.js 2.0 is fully backward compatible with Analytics.js Classic. To upgrade your sources, follow the manual upgrade steps below, or see the schedule for automatic migration.
 
-## Manual migration
+## Manual upgrade
 
-To migrate a source to Analytics.js 2.0:
+To upgrade a source to Analytics.js 2.0:
 
 1. In your Segment workspace, open the **Connections** page.
-2. Open the Javascript source you will migrate.
+2. Open the Javascript source you will upgrade.
 3. On the **Settings** tab, open the **Analytics.js** category.
 4. Enable the flag for Analytics 2.0.
 5. Within 5 minutes, the source receives Analytics.js 2.0. No code or tag changes required.
 6. Open the Debugger to ensure that events are flowing as expected.
 
 ## Automatic migration
 
-Analytics.js sources will migrate to Analytics.js 2.0 on the date below, according to the account tier. On the date listed, Segment will migrate all Analytics.js sources within the associated account tier.
+Analytics.js sources will upgrade to Analytics.js 2.0 on the date below, according to the account tier. On the date listed, Segment will upgrade all Analytics.js sources within the associated account tier.
 
 | Segment Plan | Upgrade Date |
 |--------------| -------------|