Update issue, encryption:scan:legacy-format responds with: [...] does not have a proper header

Nextcloud version : 20.0.9
Operating system and version: Centos7
Apache: httpd-2.4.6-97.el7.centos.x86_64
PHP version: PHP 7.3.x

The issue you are facing:
Hello, after the most recent update of my Nextcloud instance there is this message in my overview section:

The old server-side-encryption format is enabled. We recommend disabling this. For more details see the documentation.

When I run the command mentioned in the documentation, “sudo -u apache php occ encryption:scan:legacy-format” it gives me errors, saying that some files do not have proper headers.

  1. What does that tell me?
  2. Can this be ignored?
  3. Can I safely disable legacy encryption?
  4. How can I find out what that is supposed to mean?
  5. Is there detailed documentation so I can help myself?

The official “Documentation”, I would call this a note rather, doesn’t help: https://docs.nextcloud.com/server/20/admin_manual/configuration_files/encryption_migration.html#encryption-migration.
Maybe someone with the proper background might elaborate on this?

Steps to replicate it:

  1. Update NC (at the time of writing this, to version 20.0.9)
  2. Navigate to (using a NC admin account): Administration → Overview
  3. Find the message: The old server-side-encryption format is enabled. We recommend disabling this. For more details see the documentation.
  4. Run sudo -u apache php occ encryption:scan:legacy-format
  5. Be confused about what to do with this message???

Then run said command “occ encryption:scan:legacy-format” the only output it provides me is:

[/path/to/filename] does not have a proper header
[/path/to/filename] does not have a proper header
[/path/to/filename] does not have a proper header
[/path/to/filename] does not have a proper header
[...]

The output of your config.php file in /path/to/nextcloud

[...]
'maintenance' => false,
[...]
'encryption.legacy_format_support' => true,
'encryption.key_storage_migrated' => false,
[...]

Thx <3