Exciting news!
Our project result AuTo has gone public! With STACK 4.5 out now, people can implement GeoGebra applets easily into their STACK questions. One of the big goals of our project has finally been reached.
Many thanks to all involved, especially our project member Tim Lutz, who has been working on the code from early on.
For all those who would like to know how to implement GeoGebra applets into STACK 4.5, see the documentation here: http://docs.stack-assessment.org/en/Authoring/GeoGebra/
And for all those who like to see AuTo in action see here: https://stack.authomath.org/