Redmine

Good morning everyone,

in the company we have redmine 3.4.11 in production. Debian OS 9.
I inherit this installation not made by me.

below are the characteristics:
Environment:
Redmine version 3.4.11.stable
Ruby version 2.5.5-p157 (2019-03-15) [x86_64-linux-gnu]
Rails version 4.2.11.1
Environment production
Database adapter PostgreSQL
SCM:
Git 2.20.1
Filesystem
Redmine plugins:
view_customize 2.4.0

therefore the need arises to migrate everything to a new VM with debian 11.
I installed redmine on the new VM and everything works fine. I have always used PostgreSQL and replicated and updated the plugin which is compatible with version 5.0.5.

below are the characteristics:
Environment:
Redmine version 5.0.5.stable
Ruby version 3.1.4-p223 (2023-03-30) [x86_64-linux]
Rails version 6.1.7.2
Environment production
Database adapter PostgreSQL
Mailer queue ActiveJob::QueueAdapters::AsyncAdapter
Mailer delivery smtp
Redmine settings:
Redmine theme Default
SCM:
Git 2.30.2
Filesystem
Redmine plugins:
view_customize 3.3.0

So I transferred the contents of the files folder and gave the permissions.

I made a PostgreSQL backup following this guide: https://www.redmine.org/projects/redmine/wiki/RedmineBackupRestore
but when i go to import the database on the new machine i get a lot of errors. Projects are imported, but users and trackers are not. It is also possible to view old tickets, but when opening I receive an error. Could you show me a step by step guide on how to import the database on the new VM?

ps. I can't test on the old redmine installation. it is not a VM and there are no disaster recovery rules.

many thanks to whoever wants to help me.