Nextcloud Upgrade 13 -> 15

[MVTec]

Hello, I am trying to upgrade Nextcloud 13 to 15 using docker-compose from https://github.com/nextcloud/docker/blob/master/.examples/docker-compose/insecure/postgres/apache/ I see database version mismatch in logs, expected 11 but created using 10. So I got a fresh install and it runs , now I want to import DB , for this I have created dump from version 13 container (superuser postgres) and trying to import in version 15 container. But it doesn't have any superuser. Because of which statements fail. Please suggest how to proceed.

 # docker exec -ti nextcloud15_db_1 psql -U nextcloud
psql (11.2)
Type "help" for help.

nextcloud=> \du
           List of roles
 Role name | Attributes | Member of
-----------+------------+-----------
 nextcloud |            | {}

ERROR:  syntax error at or near "pg_dumpall"
LINE 1: pg_dumpall: executing SELECT pg_catalog.set_config('search_p...
        ^
SET
SET
ERROR:  syntax error at or near "pg_dumpall"
LINE 1: pg_dumpall: executing SELECT oid, rolname, rolsuper, rolinhe...
        ^
ERROR:  must be superuser to alter superusers
ERROR:  syntax error at or near "pg_dumpall"
LINE 1: pg_dumpall: executing SELECT provider, label FROM pg_catalog...
        ^
ERROR:  role "postgres" does not exist
ERROR:  syntax error at or near "pg_dumpall"
LINE 1: pg_dumpall: executing SELECT setconfig[1] FROM pg_db_role_se...
        ^
ERROR:  syntax error at or near "pg_dumpall"
LINE 1: pg_dumpall: executing SELECT setconfig[1] FROM pg_db_role_se...
        ^
ERROR:  database "nextcloud_db" does not exist

[MVTec]

I was able to get it running, however it is not fully functional, doesn't allow deleting user , on many operations displays "Interner Serverfehler" screenshot attached

moreover there are discrepancies in database structure , it seems some tables habe been deleted ´´´ admin_sections admin_settings group_folders group_folders_applicable personal_sections personal_settings registration users_external

´´´ and new added like ´´´ calendar_invitations calendar_resources calendar_rooms directlink ldap_group_mapping ldap_group_mapping ldap_user_mapping twofactor_providers whats_new ´´´

Please suggest how to proceed

[J0WI]

Skipping major releases is not supported. Please upgrade 13 -> 14 -> 15.

[bonanza123]

Maybe you want to head over to https://help.nextcloud.com/ for help. Also, jumping over releases is usually not advised. Mabe 13->14->15 would have worked better.

[MVTec]

Thanks a lot , it worked flawlessly