There is now an official 64bit version of Raspbian, and so a new LibreServer [1] image has been made which is based on that. In theory this should have better performance on the hardware, and I've seen various claims about that. But often performance benchmarks are heavily based around graphics, and on a server graphics aren't used, so the actual performance improvement might be quite modest.
Even so, if you're on a tight energy budget or running on solar then every saved electron counts.
In the process of making the new image there have been a few bug fixes, and I noticed that the way in which the system was detecting whether it was a Raspberry Pi or not needed to change.
You can get the new image here [2], or there is also a magnet link [3] for torrenting.