I have released ProGuard 4.9 beta2. This version contains a few new features and bug fixes, collected since the previous release. Notably, ProGuard now provides a Gradle task. It also implements additional optimizations to remove unnecessary string operations. The optimization step has a more refined analysis of static initializers, which allows to remove more unused classes and inline more methods.
As usual, the release is fully compatible with previous releases, so upgrading is essentially a matter of replacing jars. Please try it out and report any problems.