Update README.md

Author: uerceg

README.md

@@ -44,6 +44,7 @@ our [Android web views SDK guide](doc/english/web_views.md).
       * [Adjust device identifier](#di-adid)
    * [User attribution](#user-attribution)
    * [Push token](#push-token)
+   * [Track additional device identifiers](#track-additional-ids)
    * [Pre-installed trackers](#pre-installed-trackers)
    * [Deep linking](#deeplinking)
       * [Standard deep linking scenario](#deeplinking-standard)
@@ -744,7 +745,27 @@ We still support the previous signature of the same method:
 Adjust.setPushToken(pushNotificationsToken);
 ```
 
-Push token is needed for uninstall tracking feature.
+Push token is used for Audience Builder and client callbacks and needed for the upcoming uninstall tracking feature.
+
+### <a id="track-additional-ids"></a>Track additional device identifiers
+
+If you are distributing your app **outside of Google Play Store** and would like to track additional device identifiers (IMEI and MEID), you need to explicitly instruct Adjust SDK to do so. You can do that by calling `setReadMobileEquipmentIdentity` method of `AdjustConfig` instance and passing `true` parameter to it. **Adjust SDK doesn't collect these identifiers by default**.
+
+```java
+AdjustConfig config = new AdjustConfig(this, appToken, environment);
+
+config.setReadMobileEquipmentIdentity(true);
+
+Adjust.onCreate(config);
+```
+
+You will also need to add `READ_PHONE_STATE` permission to your `AndroidManifest.xml` file:
+
+```xml
+<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
+```
+
+In order to use this feature, additional steps in your Adjust dashboard will be required. For more information, please contact your dedicated Account Manager or write an E-Mail to [email protected].
 
 ### <a id="pre-installed-trackers"></a>Pre-installed trackers