diff --git a/docs/migration-guide.md b/docs/migration-guide.md
index 107f5e23..a44267db 100644
--- a/docs/migration-guide.md
+++ b/docs/migration-guide.md
@@ -2,7 +2,95 @@
 
 ## From v2 to v3
 
-<!-- TODO -->
+The below is a quick summary of steps to take when migrating from v2 to v3 of RNFirebase. Please see the [v3 change log](https://github.com/invertase/react-native-firebase/releases/tag/v3.0.0) for detailed changes.
+
+** Please note, we're now using `Apache License 2.0` to license this library. **
+
+##### 1) Install the latest version of RNFirebase:
+> `npm i react-native-firebase@latest --save`
+
+
+
+
+##### 2) Upgrade react-native version (only if you're currently lower than v0.48):
+
+- Follow the instructions [here](https://facebook.github.io/react-native/docs/upgrading.html)
+
+
+
+
+##### 3) Update your JS code to reflect deprecations/breaking changes:
+
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [app] `new RNFirebase()` is no longer supported. See below for information about app initialisation.
+- ![#f03c15](https://placehold.it/15/fdfd96/000000?text=+) **[deprecated]** [app] `initializeApp()` for apps that are already initialised natively (i.e. the default app initialised via google-services plist/json) will now log a deprecation warning.  
+  - As these apps are already initialised natively there's no need to call `initializeApp` in your JS code. For now, calling it will just return the app that's already internally initialised - in a future version this will throw an `already initialized` exception.
+  - Accessing apps can now be done the same way as the web sdk, simply call `firebase.app()` to get the default app, or with the name of specific app as the first arg, e.g. `const meow = firebase.app('catsApp');` to get a specific app.
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [auth] Third party providers now user `providerId` rather than `provider` as per the Web SDK.  If you are manually creating your credentials, you will need to update the field name.
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [database] Error messages and codes internally re-written to match the web sdk
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [database] `ref.isEqual` now checks the query modifiers as well as the ref path (was just path before). With the release of multi apps/core support this check now also includes whether the refs are for the same app.
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [database] on/off behaviour changes. Previous `off` behaviour was incorrect. A `SyncTree/Repo` implementation was added to provide the correct behaviour you'd expect in the web sdk. Whilst this is a breaking change it shouldn't be much of an issue if you've previously setup your on/off handling correctly. See #160 for specifics of this change.
+- ![#f03c15](https://placehold.it/15/f03c15/000000?text=+) **[breaking]** [storage] UploadTaskSnapshot -> `downloadUrl` renamed to `downloadURL` to match web sdk
+
+
+
+
+
+
+##### 4) Android - Update `android/build.gradle`:
+
+
+- Check you are using google-services 3.1.0 or greater:
+- You must add `maven { url 'https://maven.google.com' }` to your `android/build.gradle` as follows:
+```groovy
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:2.2.3'
+        classpath 'com.google.gms:google-services:3.1.0' // CHECK VERSION HERE
+
+        // NOTE: Do not place your application dependencies here; they belong
+        // in the individual module build.gradle files
+    }
+}
+
+allprojects {
+    repositories {
+        mavenLocal()
+        jcenter()
+        maven {
+            // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
+            url "$rootDir/../node_modules/react-native/android"
+        }
+        // ADD THIS SECTION HERE
+        maven {
+            url 'https://maven.google.com'
+        }
+    }
+}
+```
+
+
+
+
+
+##### 5) Android - Update `app/build.gradle`:
+
+
+- You must update all your Firebase dependencies to 11.3.0.
+
+
+
+
+
+##### 6) iOS - Update podfile:
+
+- You need to check that you're running at least version 4.2.0 of the Firebase Pods
+  - Run `pod outdated`
+  - Run `pod update`
 
 ## From v1 to v2