No, it’s only possible to buy the latest version.
Compared to Cubase 4, Cubase 9.5 greatly improves the workflow when working with MIDI. For example, you can double click to add new notes, there are chord drawing tools with easy inversion capabilities, adjusting note lengths and legato is way easier, you can draw MIDI controllers directly into a note by double clicking it, and much, much more. The most used MIDI tools are now available to the left of the piano roll.
Cubase 4 looks like a stone age tool by comparison. It also has issues if you try to run it on a modern operating system, and the price to upgrade from Cubase 4 to the latest version (if you feel like it or need to) isn’t cheap. Absolutely not worth it.
If Cubase Pro is too expensive for you, consider buying Cubase Artist, it’s also pretty powerful. Or you could try Cubase Elements, which is the modern equivalent of Cubasis VST.