.NET Framework released in November 2019 Quality Summary preview. This version includes for Windows 8.1, Server 2012 R2, Server 2012, Windows 7 SP1, the following quality Server 2008 R2 SP1 and Server .NET Framework of 2008 SP2 and reliability improvements.
ASP.NET
Currently, when HttpCookie.SameSite value is "None", ASP.NET will issue SameSite cookie headers to accommodate the forthcoming changes in Chrome's processing of SameSite cookie. As part of this change, although you can override these values in web.config, but FormsAuth and SessionState cookie will also use SameSite = "Lax" issue, rather than the previous default value of "None".
CLR
Solve some ClickOnce applications or use restricted permission set creates a default AppDomain of the application, the problem may be observed application is started or an application running on failure or unexpected behavior.
WCF
When using WCF TCP Port Sharing to solve the competition problems in this condition, the session establishment handshake part of the disconnected client may lead to WCF service is no longer able to accept new connections.
When the IIS worker process has many uses TCP port sharing WCF TCP Web service, and the work process crashes under high CPU load, TCP Port Sharing reinitialized during competition may lead to some endpoint can not accept client connections. Added to enable a AppSetting when this happens retry initialization.
WPF
To solve some problems on hosting the .NET Framework 4.8 Per-Monitor System-Aware Unaware child window or running Aware WPF applications may occasionally collapse due to collapse of System.Collections.Generic.KeyNotFoundException.
SQL
Due to solve a malformed string result can not print information SqlClient Bid tracking.
Details: https://devblogs.microsoft.com/dotnet/net-framework-november-2019-preview-of-quality-rollup/