Although most of the attention is on .NET Core, development continues on the original .NET Framework. Microsoft has recently released a preview of .NET Framework 4.7.2 with updates to ASP.NET, ADO.NET, WCF, WPF, and even Windows Forms. You can see the complete release notes on GitHub.
ADO.NET
The big news in this release is support for Azure AD Universal and Multi-factor authentication (MFA). Beyond that there are numerous driver bugs such as XEvents being lost and reliability issues in SqlBulkCopy.
ASP.NET
The headliner for ASP.NET is dependency injection support for Page, Custom Handler and User controls. Details have not yet been released on exactly what this means in terms of design patterns and capabilities.
Another feature is the ability to control the SameSite property on cookies. Previously it was only possible to set SameSite using URL rewriter rules.
Base Class Library
HashSet is getting a lot of attention with performance and memory consumption improvements, a way to specify the default capacity, a TryGetValue method, and a ToHashSet extension method for LINQ support.
ConcurrentDictionary is also seeing a performance improvement and new GetOrAdd/AddOrUpdate overloads.
Using code from .NET Core, ReaderWriterLockSlim handles contention better by reducing the likelihood of writer starvation and not waking more than one writer.
Other minor performance improvements affect DateTime, file and directory enumeration, TextInfo, Comparer/EqualityComparer.Default, Buffer, and ManualResetEventSlim.
CLR
There is very little in the way of features, but this release contains a lot of reliability fixes to areas such as code generation, garbage collection, and error recovery/reporting.
ClickOnce
High DPI support can now be enabled in a ClickOnce manifest, which is necessary for some high-resolution monitors. Narrator, an important accessibility tool, now works correctly with the ClickOnce installer.
Networking
There are important bug fixes for Uri, HttpClient, SmtpClient, Socket, and WebSocket, but no new features.
WCF
The SvcTraceViewer tool, which is used to diagnose WCF issues, has received an updated UI to "be more logical". It, and the SvcConfigEditor tool, have also been updated to comply with accessibility standards.
Windows Forms
Long standing bugs such as DataGridView.Dispose throwing a NullReferenceException have been fixed. [Editor’s note: I hope this is the one I reported back in 2008.] Surprisingly, the DataGridView also got a new feature: the F3 command can be used to update the sort order in the table.
More importantly, lots of effort was put into accessibility issues such as keyboard accessibility support for tool strips. However, to fully take advantage of these changes the application will have to be recompiled for .NET Framework 4.7.2.
Windows Workflow
There are several reliability fixes, but no new features.
WPF
Bug fixes dealing with memory leaks, data corruption, and crashes are being addressed.