help with upgrade from v15 to v16 rhel z/linux needed

Dears,

We need help with upgrading PostgreSql v15 to v16 on z/Linux Red Hat Enterprise Linux 8 for IBM zSystems -AppStream.
We have tried 3 methods so far, all fail.

Server connection to external pages is prohibited, we cannot download the packaged directly from the web link
We were able to disable module 15 and enable module 16, it replaced only v15 binaries, so we could not proceed with upgrade using pg_upgrade --link, because v15 were gone.....
Backup/ restore failed also with missing database, users, etc.

When we tried module switch (disable v15, enable v16), yum install postgresql-update/ postgresl-setup --upgrade, all went fine (i.e upgrading database OK), service 16 started,
Binaries were installed under different path, but database and users were missing. We have recreated the database, restore failed, users denied, and so on.....

yum.repos.d]# yum module list | grep postgres
postgresql 15 [e] client, server [d] PostgreSQL server and client module
postgresql 16 client, server [d] PostgreSQL server and client module

rpm -qa | grep "postgresql"
postgresql-private-libs-16.8-1.module+el8.10.0+22867+e4e13b1c.s390x
postgresql-private-devel-16.8-1.module+el8.10.0+22867+e4e13b1c.s390x
postgresql-16.8-1.module+el8.10.0+22867+e4e13b1c.s390x
postgresql-server-16.8-1.module+el8.10.0+22867+e4e13b1c.s390x

Could you advise us, what might be wrong, which package is suitable and steps to do the upgrade, please? Is it something wrong with packages we have, or module misconfiguration, or....

Regards,

Evelina Angelova

DBA Administrator

Evelina(dot)Angelova(at)kyndryl(dot)com

Kyndryl Client Center, s.r.o.

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