base 5.0.1 to 6.6.1

[license_all]

We bought the license and installed the latest version 6.6.1.
We have an old database backup from version 5.0.1.
How to correctly restore a backup from an old version to a new one?

[license_all]

I do not have a server with version 5.0.1. The upgrade process is too complicated. Therefore, a new clean server with a clean database was created. The database will be populated manually, the data will be looked at in pdf files uploaded beforehand.
The server does not have access to the Internet. Maybe he needs access to the Internet to make the mistake disappear?
I pressed the "no longer show" button, but after a while this message came out again.

[AnnWorley]

I am happy to hear you are upgrading Confluence. The upgrade from 5.x to 6.x is a major one. There is no way to upgrade by restoring a backup because there are upgrade tasks that have to run which make changes to the database and other components.

Please follow our detailed guide: Upgrading Confluence. Especially with such a major upgrade, we strongly recommend upgrading in a test environment first, to avoid surprises and unplanned downtime in Production. This article should help: Create a staging environment for upgrading Confluence

I look forward to any follow up questions. Please keep us posted on how you progress.

[license_all]

There is no intermediate server. There is only an old backup. We decided to create a new clean database, since it is not possible to restore the old backup by your words. There is an error - Confluence administration - Troubleshooting and support tools - Problems detected - Administration - Error End of Life. Why does this error occur? How can I fix it?

[Nic Brough -Adaptavist-]

The end of life error is a warning, telling you that your version is out of support.  You can ignore it.

Your process must be to create an old version of Confluence, the same as the version that was backed up, and restore your backup into it.  You then need to step through the version upgrades recommended in the docs Ann linked to.

[license_all]

A new server, a clean database. The program version is 6.6.1. The license was purchased. What means is not supported?

[Nic Brough -Adaptavist-]

It doesn't matter, it's only a warning, although it might be hinting that you've already tried to do something with your old data.

I would concentrate on your original question.  You need to get that backup working with an old install of 5.0.1 so you can upgrade it.