On August 21 / 22 I will update projects.vdr-developer.org to a new Redmine version, so please be prepared for some service downtime.
I didn't ran into any problems when updating Redmine from 0.7.4 to 1.0.0. Everything seems to run fine. If you encounter any problems, please file a bug report here:
http://projects.vdr-developer.org/projects/project-management/issues/new
For a list of changes since 0.7.4 see:
http://www.redmine.org/wiki/Redmine/Changelog
Tobias