Add information about traits and adding to context for new mobile libraries

Author: ashton-huxtable

src/connections/spec/common.md

@@ -210,6 +210,8 @@ Other libraries only collect `context.library`, any other context variables must
 
 - userAgentData is only collected if the [Client Hints API](https://developer.mozilla.org/en-US/docs/Web/API/User-Agent_Client_Hints_API){:target="_blank"} is available on the browser.
 
+- Traits are no longer collected and appended to the context of subsequent calls in the new mobile libraries (Swift, Kotlin, and React Native). 
+
 To pass the context variables which are not automatically collected by Segment's libraries, you must manually include them in the event payload. The following code shows how to pass `groupId` as the context field of Analytics.js's `.track()` event:
 
 ```js
@@ -218,6 +220,11 @@ analytics.track("Report Submitted", {},
 );
 ```
 
+In order to add fields to the context object in the new mobile libraries, you must utilize a custom plugin. Documentation for creating plugins for each library can be found here:
+- [React Native](https://segment.com/docs/connections/sources/catalog/libraries/mobile/react-native/#plugin-architecture){:target="_blank"}
+- [Swift](https://segment.com/docs/connections/sources/catalog/libraries/mobile/apple/swift-plugin-architecture/){:target="_blank"}
+- [Kotlin](https://segment.com/docs/connections/sources/catalog/libraries/mobile/kotlin-android/kotlin-android-plugin-architecture/){:target="_blank"}
+
 
 ## Integrations