Docs: "Custom Hydration Modes" code sample is deprecated

[ThomasLandauer]

When following https://www.doctrine-project.org/projects/doctrine-orm/en/2.7/reference/dql-doctrine-query-language.html#custom-hydration-modes I'm getting:

Call to deprecated method fetchAll() of class Doctrine\DBAL\Driver\ResultStatement:
Use fetchAllNumeric(), fetchAllAssociative() or fetchFirstColumn() instead.

I wanted to fix it, but it looks like everything in ResultStatement is deprecated. So what's the new way of setting up a custom hydrator?

[webmasterMeyers]

Was this ever figured out? as it says use fetchFirstColumn() but this function does not exist anywhere