If you are looking for current iZotope mastering tools that are fully supported on modern systems: Izotope Plugins not recognized on new install on new laptop
(which was famously redesigned in later versions), Ozone 5 remains a staple for those seeking a particular "analog" warmth. Key Features that Made Ozone 5 a Classic Mastering Tutorial: iZotope Ozone 5 Maximizer - Part 6 vst plugin izotope ozone 5 vst3 link
You can find the official, original installers for both Windows and macOS directly on the iZotope Legacy Products If you are looking for current iZotope mastering
By linking Ozone 5 to his DAW via VST3, Jake was able to harness the plugin's advanced features and take his music production to new heights. The VST3 version is bundled inside the 5
iZotope no longer hosts a public "VST3 only" download. The VST3 version is bundled inside the 5.0.4+ installer.