What is MiKTeX NEXT?
The MiKTeX NEXT repository contains the latest MiKTeX updates.
How the get updates from the MiKTeX NEXT repository
The MiKTeX package management tools offer an option to switch to the MiKTeX NEXT repository.
When using the wizard, you can set a checkmark in the box labeled "Get pre-release (experimental) packages":
It may be necessary to run the wizard multiple times.
What are the risks?
The MiKTeX NEXT repository may contain packages that have not been extensively tested.
But because you can always roll back MiKTeX to a stable state by switching back to the main (stable) repository, it is in most cases not problematic to give MiKTeX NEXT a try.
How to go stable again
If you change your mind, you can get back the officially released MiKTeX version. Just run the Update Wizard and switch back to the stable repository by removing the checkmark.