Merge pull request #721 from OneSignal/addMigrationWarning

Add migration warning to readme and migration guide

MIGRATION_GUIDE_v3_to_v5.md

@@ -1,4 +1,19 @@
 # Unity v5.0.0 Migration Guide
+
+#### ⚠️ Migration Advisory for current OneSignal customers
+
+Our new [user-centric APIs and v5.x.x SDKs](https://onesignal.com/blog/unify-your-users-across-channels-and-devices/) offer an improved user and data management experience. However, they may not be at 1:1 feature parity with our previous versions yet.
+
+If you are migrating an existing app, we suggest using iOS and Android’s Phased Rollout capabilities to ensure that there are no unexpected issues or edge cases. Here is the documentation for each:
+
+[iOS Phased Rollout](https://developer.apple.com/help/app-store-connect/update-your-app/release-a-version-update-in-phases/)
+
+[Google Play Staged Rollouts](https://support.google.com/googleplay/android-developer/answer/6346149?hl=en)
+
+If you run into any challenges or have concerns, please contact our support team at [email protected] 
+
+---
+
 In this release, we are making a significant shift from a device-centered model to a user-centered model.  A user-centered model allows for more powerful omni-channel integrations within the OneSignal platform.
 
 This migration guide will walk you through the Unity SDK v5.0.0 changes as a result of this shift.

README.md

@@ -3,6 +3,21 @@
 </p>
 
 # OneSignal Unity SDK
+
+#### ⚠️ Migration Advisory for current OneSignal customers
+
+Our new [user-centric APIs and v5.x.x SDKs](https://onesignal.com/blog/unify-your-users-across-channels-and-devices/) offer an improved user and data management experience. However, they may not be at 1:1 feature parity with our previous versions yet.
+
+If you are migrating an existing app, we suggest using iOS and Android’s Phased Rollout capabilities to ensure that there are no unexpected issues or edge cases. Here is the documentation for each:
+
+[iOS Phased Rollout](https://developer.apple.com/help/app-store-connect/update-your-app/release-a-version-update-in-phases/)
+
+[Google Play Staged Rollouts](https://support.google.com/googleplay/android-developer/answer/6346149?hl=en)
+
+If you run into any challenges or have concerns, please contact our support team at [email protected] 
+
+---
+
 A free email, sms, push notification and in app messaging solution for mobile applications built through Unity.
 
 [OneSignal](https://onesignal.com) provides a fully array of omni-channel messaging solutions across: