I have the feature "nfs" enabled via the gui.
I can mount an nfs share fine, for example this command works fine:
mount -t nfs 10.10.10.10:/mnt/data/files /mnt/files
But if I try the same command using nfs4:
mount -t nfs4 10.10.10.10:/mnt/data/files /mnt/files
I see a denied error in syslog...