Attempting to install or uninstall results in the error "Cannot create a file when that file already exists.”
For some reason, Visual Studio extensions can get in a weird state where you've uninstalled the VSIX extension, but some files were left behind. To work around this issue:

1. Exit Visual Studio
2. Open the following folder (it might be on a different drive on your machine)
    C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\Extensions\Microsoft Corporation\NuGet Package Manager\<version>\
3. Delete all the files with the .deleteme extensions.
4. Re-open Visual Studio
After following these steps, you should be able to continue.

For .NET and cloud developers, we’ve focused on improving the inner-loop dev experience. New .http/.rest files make it easier to test and iterate on your APIs directly in Visual Studio, while improved Dev Tunnels help streamline the configuration and management of your webhooks. We’ve also made it easier than ever to deploy your ASP.NET apps to containers.

Game developers can now view properties from base classes modified in an Unreal Blueprint asset without leaving the IDE. Visual Studio has improved the cross-platform development experience with a new remote file explorer, Linux Console output to the Integrated Terminal window, dev container improvements, and more.

Beyond individuals, Visual Studio also has new features to better support dev teams at scale, with exportable configuration files and a persistent update toggle helping ensure everyone on your team is working from the latest version of the tool.

This blog covers several of the top new features in Visual Studio 17.5—to see some in action, watch the Visual Studio 17.5 release video. As always lot of these features come straight from your feedback and suggestions. Your feedback is critical to help us make Visual Studio the best tool it can be! 

• Fixed: Android SDK not found after upgrade to 16.2
• Fixed: VS won't start after update with message tht setup is complete.
• Fixed an issue resulting in an installer verification or manifest verification fail when user is updating through the setup UI.
• Fixed an issue that caused Visual Studio to crash or stop responding during shutdown.
• Fixed a timing-related issue while saving changed Xamarin.Android project properties or building the project that resulted in the product to stop responding.
• Fixed an issue with Visual Studio crashing when C# users typed above a namespace.
• Fixed an issue preventing SSIS packages from successfully running in some circumstances after reloading a solution. 

Team Explorer support for TLSv1.2

• We have updated the Git and the Git Credential Manager components that ship in Visual Studio.
• The optional Git for Windows component has also been updated.
• This update allows Git to connect to services that have deprecated support for TLSv1 and TLSv1.1 in favor of TLSv1.2.

Issues Fixed in this Release

These are the customer-reported issues addressed in this release:

• Projects targeting .NET Core 2.1 or newer are not supported by Visual Studio 2017 version 15.5.
• Fixed issue where installation of the SDK for .NET Core 2.1 or newer would cause the option to create ASP.NET Core 2.0 Web applications to disappear. 

مدلسازی نمونه‌ی آن به صورت زیر است:

    public class UIModel
    {
        public int PersianYear { set; get; }

        public int[] SelectedPersianMonths { set; get; }
    }