Some of the changes:

• System.Text.Json now provides the JsonSchemaExporter type, which supports generating a JSON schema that represents a .NET type.
• System.Text.Json: The JsonObject type now exposes ordered-dictionary-like APIs that enables explicit property order manipulation
• [GeneratedRegex] on properties
• The Regex class provides a Split method, similar in concept to the String.Split method. With String.Split, you supply one or more char or string separators, and the implementation splits the input text on those separators.
• Generic OrderedDictionary<TKey, TValue>
• ReadOnlySet<T>
• new Base64Url class
• System.Diagnostics.Metrics now provides the Gauge instrument
• NuGetAudit now raises warnings for vulnerabilities in transitive dependencies
• dotnet nuget why
• MSBuild BuildChecks
• C#: Partial properties
• ASP.NET Core: Fingerprinting of static web assets