Cubase 5, released in 2009, is now considered "unsupported software" by Steinberg . While it is no longer sold, users who already own a license can still download and set it up on modern PCs using official archive links and specific compatibility settings.
One major advantage of Cubase 5 is that it runs on hardware that would laugh at modern DAWs. Here is the official requirement sheet: Cubase 5 Setup Download For Pc