Btw, Syncthing is a
lot easier than Owncloud if you just want to sync some files.
I'm trying to avoid investigating the sync.koreader.rocks server myself as I'd just waste a lot of time looking into how it's set up etc. before I could get around to fixing it, but I've relayed a message to those who should be in the know. (Unfortunately busy, busy, busy.
)
It also looks like the code may not have switched the default to sync.koreader.rocks yet, but as I don't really know about this sync thing I don't know if that's safe or if there should be some kind of migration. Then again, if it isn't working right now anyway then I guess it doesn't really matter.