There are several sources for more consistent icon sets with free licenses, where we would be able to generate SVG-based exports. Most of these sets are unicoloured, what would be a huge optical change. On the other hand it would give us the possibility to apply it i.e. to buttons (or other elements) in the text color with the feature to change the colour when hovering the element (if the element is interactive).
I don't have a problem to replace the png by svg graphics. And I don't have a problem, if the icons don't look like the old ones. So, feel free to transfer the icons to a more modern style.
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences