On March 5th GitLab at collaborating.tuhh.de will be upgraded from Version 18.7 to 18.9. The Update will done between 5pm and 6pm, therefor GitLab will not be avaiable at that time.
All change can be viewed at GitLab.com.
[Update]
The update needs to be split in to two parts, therefore the update will be finished on March 10th between 5pm and 6pm