* **[Breaking change]** Bumping the minimum Android SDK version to 21 API level (Android 5.0), because old Android versions do not support root certificate authority used by App Center and would not get CA certificates updates anymore.
#### iOS
* **[Fix]** Fix `NSInvalidArgumentException` when using non-string object as a key in `NSUserDefaults`.
* **[Fix]** Fix `NSDateFormatter` initialization in a concurrent environment.
### App Center Analytics
* **[Fix]** Fix naming conflict with iOS 14 private Apple framework.
### App Center Crashes
#### iOS
* **[Improvement]** Update PLCrashReporter to 1.8.0.
### App Center Push
App Center Push has been removed from the SDK and will be [retired on December 31st, 2020](https://devblogs.microsoft.com/appcenter/migrating-off-app-center-push/).
As an alternative to App Center Push, we recommend you migrate to [Azure Notification Hubs](https://docs.microsoft.com/en-us/azure/notification-hubs/notification-hubs-push-notification-overview) by following the [Push Migration Guide](https://docs.microsoft.com/en-us/appcenter/migration/push/).
Now when Distribute is turned off in **AppCenterBehavior**, it is unlinked from the application, in order to avoid Google Play flagging the application for malicious behavior. It must be turned off for build variants which are going to be published on Google Play. See the [public documentation](https://docs.microsoft.com/en-us/appcenter/sdk/distribute/unity#remove-in-app-updates-for-google-play-builds) for more details about this change.
* **[Fix]** Fix reporting crashes caused by a thread exception.
* **[Improvement]** Use namespaced `NSUserDefaults` keys with the **MSAppCenter** prefix for all the keys set by the SDK. Fixed a few keys missing namespace.
### App Center Crashes
#### iOS
* **[Improvement]** Update PLCrashReporter to 1.6.0.
* **[Breaking change]** Bump the minimal supported Unity version from **5.6** to **2018.1**.
#### Android
* **[Fix]** Fix a Unity warning that appears when building for Android.
* **[Fix]** Fix a `java.lang.IllegalArgumentException: Unknown pattern character 'X'` in `JavaHelper.JavaDateFormatter` on Android 6.
* **[Fix]** Fix infinite recursion when handling encryption errors.
#### iOS
* **[Fix]** Fix converting string with the Unicode symbols (for example in push notification).
* **[Fix]** Optimization of release objects from memory during the execution of a large number of operations.
* **[Fix]** Disable module debugging for release mode in the SDK to fix dSYM warnings.
* **[Fix]** Fix SDK crash at application launch on iOS 12.0 (`CTTelephonyNetworkInfo.serviceSubscriberCellularProviders` issue).
* **[Fix]** The SDK was considering 201-299 status code as HTTP errors and is now fixed to accept all 2XX codes as successful.
* **[Improvement]** Replaced sqlite query concatenation with more secure bindings.
#### UWP
* **[Feature]** Support **ARM64** architecture on Unity 2019.x or above.
* **[Breaking change]** Native UWP libraries require .NETStandard now, therefore .NET 3.5 scripting runtime version and .NET scripting backend are no longer supported.
* **[Fix]** Fix the bug that caused **Install-Id** to be generated every time the application was launched.
### App Center Auth
App Center Auth is [retired](https://aka.ms/MBaaS-retirement-blog-post) and has been removed from the SDK.
### App Center Crashes
#### iOS
* **[Fix]** Fix an issue where Crashes could not be started because `StartCrashes` method was stripped for a high managed stripping level.
### App Center Distribute
* **[Feature]** Add `UpdateTrack` property to be able to explicitly set either `Private` or `Public` update track. By default, a public distribution group is used. **Breaking change**: To allow users to access releases of private groups you now need to migrate your application to call `Distribute.UpdateTrack = UpdateTrack.Private` before the SDK start. Please read the documentation for more details.
* **[Behavior change]** The public distribution is simplified to provide only one public group. If you have existing public groups defined for your application your users will receive the latest version of all public groups.
* **[Feature]** Add a **Automatic Check For Update** checkbox that can be unchecked to turn off automatic check for update.
* **[Feature]** Add a `CheckForUpdate` API to manually check for update.
#### iOS
* **[Fix]** Fix a crash when `SFAuthenticationSession` accesses the controller which is in the process of being released.
* **[Fix]** Fix sign-in when switching to third-party apps while activating updates.
#### Android
* **[Fix]** Avoid opening browser to check for sign-in information after receiving an SSL error while checking for app updates (which often happens when using a public WIFI).
* **[Fix]** When in-app update permissions become invalid and need to open browser again, updates are no longer postponed after sign-in (if user previously selected the action to postpone for a day).
* **[Fix]** Fix a possible deadlock when activity resumes during background operation for some `Distribute` public APIs like `Distribute.isEnabled()`.
### App Center Push
* **[Bug fix]** Fix triggering the notification event when restarting the application from a notification.
#### iOS
* **[Fix]** Fix an issue where Push could not be started because `StartPush` method was stripped for a high managed stripping level.
* **[Behavior change]** Fix a security issue with the `Exception` field on `ErrorReport` objects. As a result, the `Exception.StackTrace` now holds the raw stack trace, and the `Exception.Message` field is `null`.
### App Center Push
#### UWP
* **[Feature]** Allow developers to push notifications to a specific userId.
* **[Feature]** Downloading in-app update APK file has been failing on Android 4.x since TLS 1.2 has been enforced early September. The file is now downloaded using HTTPS direct connection when running on Android 4 instead of relying on system's download manager.
* **[Feature]** Fix a crash and improve logging when downloading an update fails on Android 5+.
* **[Behavior change]** If your minSdkVersion is lower than 19, Android requires the WRITE_EXTERNAL_STORAGE permission to store new downloaded updates. Please refer to the updated documentation site for detailed instructions. This is related to the download fix.
App Center Auth is a cloud-based identity management service that enables developers to authenticate application users and manage user identities. The service integrates with other parts of App Center, enabling developers to leverage the user identity to view user data in other services and even send push notifications to users instead of individual devices.
* Android from 2.2.0 to [2.3.0](https://github.com/Microsoft/AppCenter-SDK-Android/releases/tag/2.3.0)
* iOS from 2.2.0 to [2.3.0](https://github.com/Microsoft/AppCenter-SDK-Apple/releases/tag/2.3.0)
* **[Feature]** Catch "low memory warning" and provide the API to check if it has happened in last session: `Crashes.HasReceivedMemoryWarningInLastSessionAsync()`.
**Android**
* **[Bug fix]** Fixed handling the update actions in custom update dialog in Distributed module.
* Method `Crashes.HasCrashedInLastSession` renamed to `Crashes.HasCrashedInLastSessionAsync`
* Method `Crashes.LastSessionCrashReport` renamed to `Crashes.GetLastSessionCrashReportAsync` and now returns an instance of class `AppCenterTask<ErrorReport>`
* Handler for an event `Crashes.FailedToSendErrorReport` must now contain additional parameter with type `Microsoft.AppCenter.Unity.Crashes.Models.Exception`
