@mollekopf : When I understood you correctly, there is no way to provide debug symbols because of legal issues, because windows disallow them.

moved now to messageviewer.

Looks like a feature/bug of PHP where numeric array keys (here folder names) in foreach are converted to int. I'm talking about the loop in kolab_sync_backend::folders_list(). I'm working on a fix.

Albeit the suggested fix seems flawed not unlike the original code (returning null should probably happen only after an int is converted to a string, then compared to ''), I also have to note that apparently $name here is passed on as an integer and not it's string representation(???).