For the .NET runtime, Microsoft introduces experimental support for the Scalable Vector Extension (SVE), a SIMD instruction set for ARM64 CPUs. Also for the runtime, a compiler optimization called a “strength reduction” has been introduced for loops. With this capability, the loop operation is replaced with a faster, logically equivalent operation, according to release notes. Also with .NET 9 Preview 7, the runtime now has Dynamic Adaptation to Application Sizes (DATAS) enabled by default.
With the SDK, container publishing improvements have been made for insecure registries and more consistent environment variables are offered for container publishing. The preview also offers the first release of workload sets, an SDK feature that gives users more control over the workloads they install and the cadence of change of those installed workloads.
Among the library improvements, the removal of BinaryFormatter is complete. The deserializer was removed because it was deemed unsafe. Also, the preview introduces the X509CertificateLoader class, which replaces a number of “content-sniffing” methods with a “one method, one purpose” design. In another change, the System.IO.Compression APIs now use zlb-ng, yielding more efficient and consistent processing across a wider array of hardware and operating systems.