Update docs for facebook/react-native#17747

docs/android-building-from-source.md

@@ -11,9 +11,9 @@ Assuming you have the Android SDK installed, run `android` to open the Android S
 
 Make sure you have the following installed:
 
-1. Android SDK version 23 (compileSdkVersion in [`build.gradle`](https://github.com/facebook/react-native/blob/master/ReactAndroid/build.gradle))
-2. SDK build tools version 23.0.1 (buildToolsVersion in [`build.gradle`](https://github.com/facebook/react-native/blob/master/ReactAndroid/build.gradle))
-3. Android Support Repository >= 17 (for Android Support Library)
+1. Android SDK version 27 (compileSdkVersion in [`build.gradle`](https://github.com/facebook/react-native/blob/master/ReactAndroid/build.gradle))
+2. SDK build tools version 26.0.2 (buildToolsVersion in [`build.gradle`](https://github.com/facebook/react-native/blob/master/ReactAndroid/build.gradle))
+3. Android Support Repository >= 47 (for Android Support Library)
 4. Android NDK (download links and installation instructions below)
 
 ### Point Gradle to your Android SDK:

docs/getting-started.md

@@ -325,7 +325,7 @@ Once setup has finalized and you're presented with the Welcome screen, proceed t
 
 #### 2. Install the Android SDK
 
-Android Studio installs the latest Android SDK by default. Building a React Native app with native code, however, requires the `Android 6.0 (Marshmallow)` SDK in particular. Additional Android SDKs can be installed through the SDK Manager in Android Studio.
+Android Studio installs the latest Android SDK by default. Additional Android SDKs can be installed through the SDK Manager in Android Studio.
 
 The SDK Manager can be accessed from the "Welcome to Android Studio" screen. Click on "Configure", then select "SDK Manager".
 
@@ -341,12 +341,11 @@ The SDK Manager can be accessed from the "Welcome to Android Studio" screen. Cli
 
 > The SDK Manager can also be found within the Android Studio "Preferences" dialog, under **Appearance & Behavior** → **System Settings** → **Android SDK**.
 
-Select the "SDK Platforms" tab from within the SDK Manager, then check the box next to "Show Package Details" in the bottom right corner. Look for and expand the `Android 6.0 (Marshmallow)` entry, then make sure the following items are all checked:
+Select the "SDK Platforms" tab from within the SDK Manager, then check the box next to "Show Package Details" in the bottom right corner. Look for and expand the `Android 8.0 (Oreo) and API 27` entries, then make sure the following items are all checked:
 
-* `Google APIs`
-* `Android SDK Platform 23`
+* `Android SDK Platform 27`
 * `Intel x86 Atom_64 System Image`
-* `Google APIs Intel x86 Atom_64 System Image`
+* `Google APIs Intel x86 Atom_64 System Image (or Google APIs Intel x86 Atom System Image)`
 
 <block class="native mac android" />
 
@@ -358,15 +357,15 @@ Select the "SDK Platforms" tab from within the SDK Manager, then check the box n
 
 <block class="native windows mac linux android" />
 
-Next, select the "SDK Tools" tab and check the box next to "Show Package Details" here as well. Look for and expand the "Android SDK Build-Tools" entry, then make sure that `23.0.1` is selected.
+Optionally, select the "SDK Tools" tab and check the box next to "Show Package Details" here as well. Look for and expand the "Android SDK Build-Tools" entry, then make sure that `26.0.2` is selected.
 
 <block class="native mac android" />
 
-![Android SDK Manager - 23.0.1 Build Tools](/react-native/docs/assets/GettingStartedAndroidSDKManagerSDKToolsMacOS.png)
+![Android SDK Manager - 26.0.2 Build Tools](/react-native/docs/assets/GettingStartedAndroidSDKManagerSDKToolsMacOS.png)
 
 <block class="native windows android" />
 
-![Android SDK Manager - 23.0.1 Build Tools](/react-native/docs/assets/GettingStartedAndroidSDKManagerSDKToolsWindows.png)
+![Android SDK Manager - 26.0.2 Build Tools](/react-native/docs/assets/GettingStartedAndroidSDKManagerSDKToolsWindows.png)
 
 <block class="native windows mac linux android" />
 
@@ -492,7 +491,7 @@ If you have just installed Android Studio, you will likely need to [create a new
 
 <block class="native mac windows linux android" />
 
-Select the "x86 Images" tab, then look for the **Marshmallow** API Level 23, x86_64 ABI image with a Android 6.0 (Google APIs) target.
+Select the "x86 Images" tab, then look for the **Android API 27** API Level 27, x86 ABI image, or the **Oreo** API Level 26, x86_64 ABI image with a Android 8.0 (Google APIs) target.
 
 <block class="native linux android" />