Version 6.4.9 was released around April 2023. At the time, it brought several improvements and bug fixes over earlier builds, making it a stable release for many productions. The CNET Download page lists Silverstack 6.4.9 for macOS with a file size of approximately 126.48 MB, supporting Mac OS X 10.15 and later.
In exploring software solutions, always consider official channels for acquisition, the value they bring to your workflow, and the broader implications of software piracy.