Please see https://releases.xamarin.com/stable-release-cycle-8-w-ios-10-and-xcode8-support/ for the details about this release, including the steps to update or downgrade as needed.
This is a major feature release. Our thanks to all the users who tried the Beta versions and reported bugs! Many of those issues have been resolved in these latest builds. As a caution, there are still a number of those bugs that have not yet been resolved and have been moved to the follow-up bug fix releases. This release to the Stable Channel is primarily aimed at providing the best correspondence to the available Xcode 8 Final versions for users who follow a routine of prompt feature release updates. If you are not updating to Xcode 8 yet, you can optionally wait to update to Xamarin Cycle 8 versions until one of the follow-up bug fix releases.
Please file a quick bug report using the "Cycle 8" new bug form if you see any behavior that looks suspicious in these versions (and if it isn't clear whether one of the known issues in the release notes matches the problem).
Comment in this forum thread if your question is not related to a suspicious behavior after installation, but instead one of the following:
(These issues will be addressed in the follow-up bug fix releases.)
[Xamarin for Visual Studio] - Upstream non-standard behavior of NuGet Package Manager extension (Xamarin tracking bug 44146) triggered by XamarinVS 4.2 - "GetFullVsVersionString must be called on the UI thread" error appears when attempting to open Manage NuGet Packages for Solution, blocking the use of the NuGet package manager on certain systems
Temporary workaround: Install this small extension from the Xamarin VS team that will force the NuGet Package Manager to load before the Xamarin extensions.
Alternate temporary workaround: Before opening any projects, open Tools > NuGet Package Manager > Package Manager Settings to force the NuGet Package Manager extension to load before the Xamarin extensions.
[Xamarin.iOS] - 44225 - "Error: TrustFailure (CertificateUnknown)" when using Apple TLS handler to access HTTPS servers that use virtual domains (via Server Name Indication).
[Xamarin for Visual Studio], [Xamarin Studio] - 43566 - The iOS Designer initialization process will cause any running iOS 10 simulator to become non-responsive. The designer initialization happens when opening an iOS project in Xamarin Studio and during the connection to the remote Mac in Visual Studio. This issue does not affect Xcode 7.3, iOS 9.3 (and lower) simulators.
[Xamarin.Android] - 44268 - "Unexpected libzip error: Inval" when building projects that reference any of the Android Support Libraries on Windows if the user name contains any accented characters.
Temporary workaround: Create and log in with a Windows user account that has only ASCII letters in the user name.
Alternate workaround: Add a XAMARIN_CACHEPATH environment variable under Control Panel > System > Advanced system settings > Environment Variables, and set it to a path that uses only ASCII letters in the directory names.
[Xamarin.Android] - 44184 - "The "BuildApk" task failed unexpectedly. Xamarin.Tools.Zip.ZipException: Entry has been changed" when attempting to archive or deploy apps that use certain NuGet packages.
[Xamarin.UITest] - Xcode 8 removes the UI Automation API, causing "SetUp : System.InvalidOperationException : Sequence contains no matching element ... at System.Linq.Enumerable.First[TSource] ... at Xamarin.UITest.iOS.Instruments.GetAutomationTemplatePath ()" when attempting to use UITest locally.
Alternate temporary workaround: Keep using Xcode 7, or just keep Xcode 7 installed in the default location and unpack Xcode 8 side-by-side to a custom location.
[Xamarin.iOS] - "Error MT0091: This version of Xamarin.iOS requires the iOS 10.0 SDK (shipped with Xcode 8.0) when the managed linker is disabled. Either upgrade Xcode, or enable the managed linker." This message will appear when building using Xcode 7.3 or older with Xamarin.iOS 10. The issue arises because Xamarin.iOS 10 is built to include the Xcode 8 symbols. When enabled, the Xamarin managed linker can remove these unused symbols to allow building successfully against older versions of Xcode.
[Xamarin for Visual Studio] - Build > Export Android Package (.apk) and Tools > Android > Publish Android App have been replace by the Build > Archive command that is part of the new Android Archive Manager and Publishing workflow.
The Xamarin team is working to review each newly submitted bug to update its status from NEW.
NEW Reviewed Xamarin.Android 10 8 Xamarin.iOS 4 23 Xamarin.Mac 1 0 Visual Studio Extensions 13 22 Xamarin Studio 13 24 Mono 3 6 Totals 44 83
(This is a snapshot of the live report from Bugzilla as of September 26 19:03 UTC. It will be updated periodically.)