It looks like Server 1.17 will require Java version 16.
Most likely you have Java 8 installed.
in a command line enter: java -version
Here’s the link to the discussion. Upgrading Java It starts off with Java 15, but later on, it has Java 16 listed.
@hexparrot has been doing some work to update the WebUI, but I don’t know where that progress is at.
You wouldn’t use Filezilla to update the files, but you can SSH into the machine buy using PuTTy. No need to set up the KVM.