Upgrading maven wrapper can bring much enhancements when building the project, and one of the important new features is that maven is validating the wrapper against a sha256sum value to be sure that the downloaded binaries are not corrupt, much more then that it enhances the building scripts and tools and make them fit the new releases of the it's ecosystem 

Quoted from release notes : "Regression fixes and other improvements from Maven 3.9.5. All users already on Maven 3.9.x are advised to upgrade."

For more information please check the release notes on : https://maven.apache.org/docs/3.9.6/release-notes.html