The release you are referring to, , is a digital rip of the classic 1965 animated special. In the context of scene releases, a "PROPER" tag indicates that this specific version was released to fix issues found in a previous "internal" or "nuked" version from another group. Release Technical Summary
Moving from a standard digital source to a higher-quality Blu-ray or remastered master. The release you are referring to, , is
Standard surround sound for broader compatibility. The release you are referring to