[ceph-users] cephfs mount problem - client session lacks required features

Hi, During the upgrade from centos7/nautilus to ubuntu 18/nautilus (still updating the MONs) I got a cephfs client who refuses or is refused to mount the ceph fs again. The clients says: mount error 13 = Permission denied The cephmds log: lacks required features 0x0000000000001000 client supports 0x00000000000000ff The mds/mon is still centos7/nautilus. The Clients centos7 as well. Any ideas ? Thx for suggestions and hints . Best Götz