So... Inkscape can open new .ai files no problem, but Adobe won't provide support for older versions of Illustrator to open them? Wow, that's... dumb.
You could use the SVG files in the owncloud folder, but they are Inkscape SVG rather than standard SVG. The main difference is that you have layers in the Inkscape file format, and standard SVG 1.0 is single-layer only.
As far as I know, Illustrator interprets Inkscape SVG as standard SVG (though they could very easily interpret it properly, the file format is well-documented).
So it may not be ideal opening the SVG with Illustrator - it may be that you don't have separate layers, and it's all a big mess. But let's experiment - can you please try opening one of the SVGs and tell me what happens? Maybe certain Illustrator versions work with SVG better than others.
If that doesn't work well, I will save each layer of the Inkscape SVG as a standard SVG, which can then be brought into any vector program. Or you could try using Inkscape, of course
Or perhaps @OTTILIE can use Illustrator CC to save the .ai file as some kind of backwards-compatible format, if one exists?