docs: add 4.5.0 automatic push integration flags to Android migration guide + README

MIGRATION_GUIDE.md

@@ -2,6 +2,61 @@
 This document provides guidance on how to migrate from one version of the SDK to a newer version.
 It will be updated as new versions are released including deprecations or breaking changes.
 
+# 4.5.0
+
+## New Automatic Push Behaviors (Manifest Flags)
+
+SDK 4.5.0 introduces two push behaviors controlled via `AndroidManifest.xml` metadata:
+`automatic_push_open_tracking` (new, opt-in) and `automatic_push_token_forwarding` (**on by
+default**, formalizing the SDK's existing automatic token forwarding). No action is required to
+preserve your current behavior. If you manage push tokens manually and want to disable automatic
+forwarding, opt out as described below.
+
+### `automatic_push_open_tracking` (opt-in, default **off**)
+
+When enabled, the SDK automatically records push-open events without requiring you to call
+`Klaviyo.handlePush` manually in your notification interaction handler.
+
+To enable, add the following to the `<application>` element of your `AndroidManifest.xml`:
+
+```xml
+<meta-data
+    android:name="com.klaviyo.push.automatic_push_open_tracking"
+    android:value="true" />
+```
+
+This flag defaults to **off** in 4.5.0. It is expected to become the default (opt-out) in a future
+major release.
+
+### `automatic_push_token_forwarding` (default **on**)
+
+When this flag is enabled (which is the **default**), the SDK automatically registers the device's
+FCM push token with Klaviyo on your behalf — you no longer need to call `Klaviyo.setPushToken`
+manually on app startup.
+
+To opt out of automatic token forwarding and retain manual control, add the following to the
+`<application>` element of your `AndroidManifest.xml`:
+
+```xml
+<meta-data
+    android:name="com.klaviyo.push.automatic_push_token_forwarding"
+    android:value="false" />
+```
+
+### Rollout summary
+
+| Behavior | This release (4.5.0) | Future major release |
+|---|---|---|
+| `automatic_push_token_forwarding` | Default on (opt-out via manifest) | Default on |
+| `automatic_push_open_tracking` | Opt-in (default off) | Default on (opt-out) |
+
+> **Anonymous profiles:** When `automatic_push_token_forwarding` is enabled (the Android default),
+> the SDK registers the device's push token with Klaviyo automatically — at initialization, when the
+> app returns to the foreground, and whenever FCM issues a new token — which can occur before you call
+> `setProfile`, `setEmail`, or `setPhoneNumber`. This results in an anonymous profile being created in Klaviyo
+> until you provide identifying information. This is expected behavior. See
+> [Anonymous Tracking](./README.md#anonymous-tracking) in the README.
+
 # 4.3.0
 
 ## New Modules for Cross-Platform Support

README.md

@@ -347,6 +347,14 @@ Klaviyo will track unidentified users with an autogenerated ID whenever a push t
 That way, you can collect push tokens and track events prior to collecting profile identifiers such as email or
 phone number. When an identifier is provided, Klaviyo will merge the anonymous user with an identified user.
 
+> **Automatic push token forwarding:** When `automatic_push_token_forwarding` is enabled (the
+> default in SDK 4.5.0+), the SDK registers the device's push token with Klaviyo automatically — at
+> initialization, when the app returns to the foreground, and whenever FCM issues a new token — which
+> can occur before any call to `setProfile`, `setEmail`, or `setPhoneNumber`. This results
+> in an anonymous profile being created in Klaviyo until you provide identifying information.
+> This is expected behavior. To opt out, see the
+> [Migration Guide](./MIGRATION_GUIDE.md#automatic_push_token_forwarding-default-on).
+
 ## Event Tracking
 The SDK provides tools for tracking analytics events via the
 [Create Client Event API](https://developers.klaviyo.com/en/reference/create_client_event).