[ceph-users] Ceph monitor won't start after Ubuntu update

Hello Ceph-users, I've upgraded my Ubuntu server from 18.04.5 LTS to Ubuntu 20.04.2 LTS via 'do-release-upgrade', during that process ceph packages were upgraded from Luminous to Octopus and now ceph-mon daemon(I have only one) won't start, log error is: "2021-06-15T20:23:41.843+0000 7fbb55e9b540 -1 mon.target@-1(probing) e2 current monmap has recorded min_mon_release 12 (luminous) is >2 releases older than installed 15 (octopus); you can only upgrade 2 releases at a time you should first upgrade to 13 (mimic) or 14 (nautilus) stopping." Is there any way to get cluster running or at least get data from OSDs? Will appreciate any help. Thank you -- Best regards, Petr