During the last few days, we finally switched our website hosting from sourceforge to github.io. This was already planned for some time but not actually done because of lack of time. Just recently, the domain name ultrastardeluxe.org got lost to some domain grabber who is not reachable for contact. A new developer finally did all the work to initially set up the jekyll based site and also converted the already existing content to markdown. Thanks to the github hosting, any website changes can be suggested as pull request by anyone at https://github.com/UltraStar-Deluxe/ultrastar-deluxe.github.io . Once those changes are commited, they automatically are applied to the website a few minutes later.
Long story short: our new domain name is https://usdx.eu and the website is now hosted on github.