The previews of EF Core 5.0 require .NET Standard 2.1. This means:

• EF Core 5.0 runs on .NET Core 3.1; it does not require .NET 5.
  • This may change in future previews depending on how the plan for .NET 5 evolves.
• EF Core 5.0 runs on other platforms that support .NET Standard 2.1.
• EF Core 5.0 will not run on .NET Standard 2.0 platforms, including .NET Framework. 

ASP.NET Core in .NET 5 Preview 2 doesn’t include any major new features just yet, but it does include plenty of minor bug fixes. We expect to announce new features in upcoming preview releases. 

• An error occurred while generating the SSH keys. Please check that the environment is properly configured. Details: cat: /Users/cc/Library/Caches/Xamarin/XMA/Keys/1984b83a-dde9-4031-919d-b1d1b8411d0d: No such file or directory
• InvalidOperationException while debugging Xamarin Forms app
• Frame note in module in Xamarin Forms Android
• Internal compiler error is fixed and analysis for WDK completes as usual.
• We fixed an issue in the new Find in Files experience where hidden files and auto-generated files were not searchable.
• Fixed issue with deployment of UWP apps to remote machines where deployment fails with message "DEP0600: Deployment failed. DkmException - Error in the application."
• Local static variable not initialized in inlined function of class imported from dll
• VS 2019 16.5.X: Multiple startup projects while Live Visual Tree was last opened in a debug session crashes
• Fixed issues where for the C++ formatting indentation of new lines with only ending parenthesis.
• Fixed a bug preventing some users from installing 16.5
• Fix an issue where Visual Studio can crash when the display configuration changes.
• Fixed an issue causing slow downs when opening solutions that are impacting the IntelliSense code and related operations.
• Fixed a crash with the debugger that users can run into when the target application being debugged raises an exception.
• Added support for Xcode 11.4.

• A bug is fixed in loop unroller which might lead to wrong condition codes being generated in the unrolled loop.
• Fixed a bug that caused ServiceHub.Host.CLR.x64 to stop working.
• Fixes issue in Chinese version of compiler errors C4533 and C2362 which resulted in incorrect order of string substitution for those languages.
• Improved stability of the Diagnostic Tools and Performance Profiler.
• Code generation problem causing crash with pure virtual destructor in const object
• Fixed a constant evaluation regression from 16.5 Preview 2
• Fixed an issue where MacOS couldn't be paired.
• Fixed an issue where the Diagnostic Tools while debugging and Performance Profiler fail to launch on XBox devices. 

The following improvements are in Preview 1:

• Regular expression performance improvements (3-6x Faster)
• Code quality improvements in RyuJIT
• Assembly load diagnostics added to event pipe
• Event pipe profiler APIs
• .... 

WSL2 will ship with Windows 10 version 2004, with kernel updates via Windows Update 

Top Issues Fixed in Visual Studio 2019 version 16.4.6

• Miscompile, boolean condition deduced to be always true.
• Issue with loop unroll in Visual Studio 2019 compiler
• CL (VC v19.24) crashes when building in a docker volume folder
• CL (VC v19.22) crashes when it starts with the /ZI parameter in the docker container
• Compiling SSE intrinsics with MSVC compiler 19.20: compiled code yields incorrect results in one specific case
• C++ AMP code will not compile in Visual Studio 2019 16.3.1
• Sometimes coroutine_handle<>::destroy() resumes coroutine instead of destroying it.
• New Spectre mitigation options in C++ compiler: /Qspectre-load & /Qspectre-load-cf for speculative load hardening.
  

Security Advisory Notice

• CVE-2020-0793 & CVE-2020-0810 Diagnostics Hub Standard Collector Service Elevation of Privilege Vulnerability
• CVE-2020-0884 Spoofing vulnerability when creating Outlook Web -Add-in
• CVE-2020-0789 Visual Studio Extension Installer Service Denial of Service Vulnerability

Issues Fixed in 15.9.21

• Fixed a bug where the .NET Profiling tools couldn't be installed on non-enterprise versions of Visual Studio 2017 when using an offline installer.
• Fixed C++ compiler bug where a static_cast in a decltype would evaluate incorrectly. To minimize disruptions to existing codebases, in VS2017 this fix takes effect when the (newly added) /d1decltypeIdentityConversion switch is thrown.
• New Spectre mitigation options in C++ compiler: /Qspectre-load & /Qspectre-load-cf for speculative load hardening.

Security Advisory Notices

• Diagnostics Hub Standard Collector Service Elevation of Privilege Vulnerability
• A spoofing vulnerability exists when creating an Outlook Web-Addin if multi-factor authentication is enabled