September 2009: Android 1.6.

• They must explicitly request the Android.Manifest.Permission.WriteExternalStorage permission to be able to modify the contents of the SD card. (Apps targeting earlier versions will always request the permission.)
• They must explicitly request the Android.Manifest.Permission.ReadPhoneState permission to be able to be able to retrieve phone state info. (Apps targeting earlier versions will always request the permission.)
• They are assumed to support different screen densities and sizes. (Apps targeting earlier versions are assumed to only support medium density normal size screens unless otherwise indicated). They can still explicitly specify screen support either way with the supports-screens manifest tag.
• Android.Widget.TabHost will use the new dark tab background design.

Applications targeting this or a later release will get these new changes in behavior:

November 2009: Android 2.0

• The Android.App.Service.OnStartCommand(Android.Content.Intent, Android.App.StartCommandFlags, Android.App.StartCommandFlags) function will return the new Android.App.StartCommandResult.Sticky behavior instead of the old compatibility Android.App.StartCommandResult.StickyCompatibility.
• The Android.App.Activity class will now execute back key presses on the key up instead of key down, to be able to detect canceled presses from virtual keys.
• The Android.Widget.TabWidget class will use a new color scheme for tabs. In the new scheme, the foreground tab has a medium gray background the background tabs have a dark gray background.

Applications targeting this or a later release will get these new changes in behavior:

November 2010: Android 2.3

• The application's notification icons will be shown on the new dark status bar background, so must be visible in this situation.

Applications targeting this or a later release will get these new changes in behavior:

February 2011: Android 3.0.

• The default theme for applications is now dark holographic: Android.Resource.Style.ThemeHolo.
• On large screen devices that do not have a physical menu button, the soft (compatibility) menu is disabled.
• The activity lifecycle has changed slightly as per Android.App.Activity.
• An application will crash if it does not call through to the super implementation of its Android.App.Activity.OnPause method.
• When an application requires a permission to access one of its components (activity, receiver, service, provider), this permission is no longer enforced when the application wants to access its own component. This means it can require a permission on a component that it does not itself hold and still access that component.
• Android.Content.Context.GetSharedPreferences(string, Android.Content.FileCreationMode) will not automatically reload the preferences if they have changed on storage, unless Android.Content.FileCreationMode.MultiProcess is used.
• Android.Views.ViewGroup.MotionEventSplittingEnabled will default to true.
• Android.Views.WindowManagerFlags.SplitTouch is enabled by default on windows.
• Android.Widget.PopupWindow.SplitTouchEnabled will return true by default.
• Android.Widget.GridView and Android.Widget.ListView will use Android.Views.View.Activated for selected items if they do not implement Android.Widget.ICheckable.
• Android.Widget.Scroller will be constructed with "flywheel" behavior enabled by default.

Applications targeting this or a later release will get these new changes in behavior:

June 2011: Android 3.2.

• Android.Content.PM.ActivityInfo.ConfigChanges will have the Android.Content.PM.ConfigChanges.ScreenSize and Android.Content.PM.ConfigChanges.SmallestScreenSize bits set; these need to be cleared for older applications because some developers have done absolute comparisons against this value instead of correctly masking the bits they are interested in.

Update to Honeycomb MR1 to support 7 inch tablets, improve screen compatibility mode, etc.

As of this version, applications that don't say whether they support XLARGE screens will be assumed to do so only if they target Android.OS.Build.VERSION_CODES.Honeycomb or later; it had been Android.OS.Build.VERSION_CODES.Gingerbread or later. Applications that don't support a screen size at least as large as the current screen will provide the user with a UI to switch them in to screen size compatibility mode.

This version introduces new screen size resource qualifiers based on the screen size in dp: see Android.Content.Res.Configuration.ScreenWidthDp, Android.Content.Res.Configuration.ScreenHeightDp, and Android.Content.Res.Configuration.SmallestScreenWidthDp. Supplying these in <supports-screens> as per Android.Content.PM.ApplicationInfo.RequiresSmallestWidthDp, Android.Content.PM.ApplicationInfo.CompatibleWidthLimitDp, and Android.Content.PM.ApplicationInfo.LargestWidthLimitDp is preferred over the older screen size buckets and for older devices the appropriate buckets will be inferred from them.

Applications targeting this or a later release will get these new changes in behavior:

New Android.Content.PM.PackageManager.FeatureScreenPortrait and Android.Content.PM.PackageManager.FeatureScreenLandscape features were introduced in this release. Applications that target previous platform versions are assumed to require both portrait and landscape support in the device; when targeting Honeycomb MR1 or greater the application is responsible for specifying any specific orientation it requires.

Android.OS.AsyncTask`3 will use the serial executor by default when calling AsyncTask`3.execute(Params...).

October 2011: Android 4.0.

• For devices without a dedicated menu key, the software compatibility menu key will not be shown even on phones. By targeting Ice Cream Sandwich or later, your UI must always have its own menu UI affordance if needed, on both tablets and phones. The ActionBar will take care of this for you.
• 2d drawing hardware acceleration is now turned on by default. You can use Android.Resource.Attribute.HardwareAccelerated to turn it off if needed, although this is strongly discouraged since it will result in poor performance on larger screen devices.
• The default theme for applications is now the "device default" theme: Android.Resource.Style.ThemeDeviceDefault. This may be the holo dark theme or a different dark theme defined by the specific device. The Android.Resource.Style.ThemeHolo family must not be modified for a device to be considered compatible. Applications that explicitly request a theme from the Holo family will be guaranteed that these themes will not change character within the same platform version. Applications that wish to blend in with the device should use a theme from the Android.Resource.Style.ThemeDeviceDefault family.
• Managed cursors can now throw an exception if you directly close the cursor yourself without stopping the management of it; previously failures would be silently ignored.
• The fadingEdge attribute on views will be ignored (fading edges is no longer a standard part of the UI). A new requiresFadingEdge attribute allows applications to still force fading edges on for special cases.
• Android.Content.Context.BindService(Android.Content.Intent, Android.Content.IServiceConnection, Android.Content.IServiceConnection) will not automatically add in Android.Content.Bind.WaivePriority.
• App Widgets will have standard padding automatically added around them, rather than relying on the padding being baked into the widget itself.
• An exception will be thrown if you try to change the type of a window after it has been added to the window manager. Previously this would result in random incorrect behavior.
• Android.Views.Animations.AnimationSet will parse out the duration, fillBefore, fillAfter, repeatMode, and startOffset XML attributes that are defined.
• Android.App.ActionBar.SetHomeButtonEnabled(bool) is false by default.

Applications targeting this or a later release will get these new changes in behavior:

June 2012: Android 4.1.

• You must explicitly request the Android.Manifest.Permission.ReadCallLog and/or Android.Manifest.Permission.WriteCallLog permissions; access to the call log is no longer implicitly provided through Android.Manifest.Permission.ReadContacts and Android.Manifest.Permission.WriteContacts.
• Android.Widget.RemoteViews will throw an exception if setting an onClick handler for views being generated by a Android.Widget.RemoteViewsService for a collection container; previously this just resulted in a warning log message.
• New Android.App.ActionBar policy for embedded tabs: embedded tabs are now always stacked in the action bar when in portrait mode, regardless of the size of the screen.
• Android.Webkit.WebSettings.AllowFileAccessFromFileURLs and Android.Webkit.WebSettings.AllowUniversalAccessFromFileURLs default to false.
• Calls to Android.Content.PM.PackageManager.SetComponentEnabledSetting(Android.Content.ComponentName, Android.Content.PM.ComponentEnabledState, Android.Content.PM.ComponentEnabledState) will now throw an IllegalArgumentException if the given component class name does not exist in the application's manifest.
• Android.Nfc.NfcAdapter.setNdefPushMessage(android.nfc.NdefMessage, android.app.Activity, android.app.Activity...), Android.Nfc.NfcAdapter.setNdefPushMessageCallback(android.nfc.NfcAdapter.CreateNdefMessageCallback, android.app.Activity, android.app.Activity...) and Android.Nfc.NfcAdapter.setOnNdefPushCompleteCallback(android.nfc.NfcAdapter.OnNdefPushCompleteCallback, android.app.Activity, android.app.Activity...) will throw IllegalStateException if called after the Activity has been destroyed.
• Accessibility services must require the new Android.Manifest.Permission.BindAccessibilityService permission or they will not be available for use.
• Android.AccessibilityServices.AccessibilityServiceInfo.FlagIncludeNotImportantViews must be set for unimportant views to be included in queries.

Applications targeting this or a later release will get these new changes in behavior:

Android 4.2: Moar jelly beans!

• Content Providers: The default value of android:exported is now false. See the android:exported section in the provider documentation for more details.
• Android.Views.View.LayoutDirection can return different values than Android.Views.View.LayoutDirectionLtr based on the locale etc.
• Android.Webkit.WebView.AddJavascriptInterface(Java.Lang.Object, System.String) requires explicit annotations on methods for them to be accessible from Javascript.

Applications targeting this or a later release will get these new changes in behavior: