Comment 4 for bug 1907081

On Focal OVN central unit used to initialize a cluster (which means the db-*-clsuter-remote-addr parameters are set to blank):
# grep remote-addr= /etc/default/ovn-central
    --db-nb-cluster-remote-addr= \
    --db-sb-cluster-remote-addr= \

I can then install the packages from -proposed:
# apt -y install ovn-common ovn-central

I can then confirm that the cluster is still healthy:
# ovn-appctl -t /var/run/ovn/ovnsb_db.ctl cluster/status OVN_Southbound
cd89
Name: OVN_Southbound
Cluster ID: d623 (d62321da-8009-4798-bd0a-171e5678a790)
Server ID: cd89 (cd8983cc-e19a-45ee-9247-34e130927eb6)
Address: ssl:10.247.39.51:6644
Status: cluster member
Role: follower
Term: 5
Leader: b941
Vote: unknown

Election timer: 4000
Log: [2, 7533]
Entries not yet committed: 0
Entries not yet applied: 0
Connections: ->b941 ->8c5f <-b941 <-8c5f
Servers:
    cd89 (cd89 at ssl:10.247.39.51:6644) (self)
    b941 (b941 at ssl:10.247.39.127:6644)
    8c5f (8c5f at ssl:10.247.39.149:6644)

Since the focal package currently does not contain any schema changes we cannot do further checks as to the upgrade procedure actually working for Focal. We will do that as part of validating Groovy.