[German]Another short supplement to May 15, 2018: Whilst there are no preview quality rollups for Windows 7/8.1, Microsoft has managed to release Quality Rollup Preview updates for the.NET framework.
On May 15, 2018 was the third Tuesday of the month. Actually, the preview rollups for Windows 7 SP1 and Windows 8.1 should have been released last Tuesday. While updates came for Windows 10 (see Windows 10: Updates KB4134660/KB413461 released, I did not find any preview rollups for Windows 7/8.1. But Susan Bradley noticed that there is something for .NET framework.
.NET Framework May 2018 Preview of Quality Rollup
Microsoft has made the announcement in this blog post. The relevant Preview of Quality Rollups for the various .NET framework versions and platforms have been available since May 15, 2018. The following improvements were made in the Preview of Quality Rollup:
- Resolves an issue in WindowsIdentity.Impersonate where handles were not being explicitly cleaned up. 
- Resolves an issue in deserialization when using a collection, for example, ConcurrentDictionary by ignoring casing. 
- Removes case where floating-point overflow occurs in the thread pool’s hill climbing algorithm. 
- Resolves instances of high CPU usage with background garbage collection. This can be observed with the following two functions on the stack:
ntoskrnl!KiPageFault. Most of the CPU time is spent in the
ntoskrnl!ExpWaitForSpinLockExclusiveAndAcquirefunction. This change updates background garbage collection to use the CLR implementation of write watch instead of the one in Windows. 
- Fixed a problem with connection limit when using HttpClient to send requests to loopback addresses. 
- A crash can occur during shutdown of an application that hosts WPF content in a separate AppDomain. (A notable example of this is an Office application hosting a VSTO add-in that uses WPF.) 
- Addresses an issue that caused XAML Browser Applications (XBAP’s) targeting .NET 3.5 to sometimes be loaded using .NET 4.x runtime incorrectly. 
- A WPF application can crash due to a NullReferenceException if a Binding (or MultiBinding) used in a DataTrigger (or MultiDataTrigger) belonging to a Style (or Template, or ThemeStyle) reports a new value, but whose host element gets GC’d in a very narrow window of time during the reporting process. 
- A WPF application can crash due to a spurious ElementNotAvailableException. 
For the last item in the above list, Microsoft has published instructions on how to fix the problem. The preview of the Quality Rollup for.NET Framework is available via Windows Update, Windows Server Update Services (WSUS) and Microsoft Update Catalog. The download links for the Microsoft Update Catalog can be found in the blog article. Since this is a preview, I would not install it.